Flashdancer, what you wear was fashionable shortly before Cheerilee got her braces.

@Ferrotter  
At any rate, my conclusion isn’t any less valid than yours (though Occam’s Razor might suggest otherwise). That lack of evidence you brought up prevents the scale from tipping in any direction. Mr. Stripes and his daughter are not present because this episode has nothing to do with the rental of the space and they aren’t exactly what you’d call friends with Rarity. As for Coco, we know she works as a full-time costume designer, so it’s not particularly hard to imagine she was simply busy designing and making the costumes for another Bridleway show.
 
There are enough opportunities for Rarity to have interacted with DJ PON-3 to become a friends with her. The same can’t be said for those three dancers. Also, Rarity was asking around for somepony to manage her store, not play live music there. Even if DJ PON-3 could do it, there wouldn’t be any need for her to bring the dancers along. So DJ PON-3 not being able to cover does not necessarily have anything to do with those dancers.

@cloudkicker108  

 
We also haven’t seen the shop, or even Manehattan, since “The Saddle Row Review.” We couldn’t possibly have seen Rarity interact with the dancers up until this very episode, in which we are informed, canonically in the script, that Rarity asked basically everypony else she could think of first, but had to settle for Fluttershy when she couldn’t find anypony else to run the shop for her. Also, as of this episode we still haven’t seen Mr. Stripes, Plaid Stripes, or “Miss” (Coco) Pommel since “TSRR” either. Does this mean Rarity no longer interacts with any of them either? (Though Coco at least was mentioned, if not seen, last season. But does this mean Mr. and Plaid Stripes must be dead, or at least sold the building?)
 
And according to the MLP wiki Rarity did ask DJ PON-3 before she asked Fluttershy; I guess I blinked when that briefly popped up in the episode because I didn’t see that. I only found it just now, looking for how many times she (in contrast to Coco) appeared between “The Saddle Row Review” and “Fake it ‘Til You Make It.” Which is actually quite a lot. But it seems that canonically, the reason they weren’t in this episode is that DJ PON-3 couldn’t cover the store for Rarity at this time. And Rarity does continue to interact with her, and would trust her to run the store more than Fluttershy. Implying that DJ PON-3 (and therefore probably the dancers) are still associated with the store. They just couldn’t cover this particular time.
 
(Just checked the episode again on Dailymotion too; the wiki is right. At 01:56 in, during the intro, Rarity asks DJ PON-3, who shakes her head no.)
 

@Ferrotter  

 
My bad on this one. I admittedly misread that part of your comment.
 

 
Those three aren’t just acquaintances; they’re her employees and professional colleagues. Seeing as how she’s still kept all three of them around after all this time, Rarity has clearly developed a professional relationship with them. And Rarity in this episode clearly does not have time to go through another applicant cycle to find an exact replacement. She’s specifically looking somepony who can not only start working immediately but can also manage the shop without her checking in at any point. Just picking somepony off the street would clash with the latter requisite. Rarity needs someone she can truly trust her store (and its presumably expensive merchandise) with.
 

 
How an I speculating? That’s literally what’s been depicted in the show. We haven’t seen Rarity interact with those dancers since “The Saddle Row Review”.
 

 
We don’t see the dancers, DJ-Pon-3, or even any of the club equipment at Rarity For You in this episode. And unlike the other decisions, they are not a necessary aspect of the store. Also, Rarity runs a haute couture boutique, not a Hollister. While live music and dancing might be a nice touch to the celebratory atmosphere of the grand opening, that’s generally not the kind of thing Rarity’s kind of clientele would appreciate as part of the shopping experience.

A more reasonable explanation would be, “Rarity did ask them, but DJ PON-3 had a gig elsewhere so they couldn’t do it.”

@cloudkicker108  
I didn’t say Rarity leased the upper level. DJ PON-3 leased the upper level.
 
Hence, DJ PON-3 was not also paying Rarity to be in Rarity’s shop downstairs. She volunteered to take the party downstairs as a friend of Pinkie and/or Rarity, she thought Pinkie’s idea of taking the party downstairs was actually an improvement over the club upstairs, or she was actually being paid to put on a show downstairs instead of upstairs.
 
Also, Rarity is perfectly fine with qualified acquaintances rather than friends running the shop. If her three shopping assistants weren’t going with her to Canterlot, they would under any other circumstances be the ones running the shop. As they are at all other times. Plus Sassy Saddles rather than one of the Mane 6 normally runs the shop in Canterlot. (Though at this point she probably does qualify as Rarity’s friend, but certainly not at the level of one of the other Mane 6.)
 

 
Now who’s spouting unsupported speculation?
 
Fluttershy’s idea to let the raccoons stay and help out is demonstrably a permanent feature of the store.  
Twilight’s organization of the merchandise is demonstrably a permanent feature of the store.  
Rainbow Dash’s decision to hire all three salesponies is demonstrably a permanent feature of the store.  
Rarity’s shop has not gone out of business due to Mr. Stripes raising the rent until Rarity “no can afford,” nor has the shop moved. So in some sense at least Applejack’s strategy to placate Plaid Stripes must have lasted. (And it’s plainly obvious why Rarity wouldn’t have asked Plaid Stripes to run the store in her absence.)
 
So please explain what evidence you have that Rarity only interacted with DJ PON-3 and the dancers once, when nothing in the show ever said that, they were clearly as popular with the customers as any of the other ideas, and all the other Mane 6(-R) ideas to help the shop overcome its problems are demonstrably permanent. (And why despite being singled out for rejection that way, Pinkie Pie, who can’t handle rejection at all, isn’t the least bit upset that Rarity booted her idea to the curb immediately after seeing that it worked.)

@Ferrotter  
You’re way overthinking this. The only time the dancers have worked for Rarity was for that one gig during Rarity4U’s grand opening. That also the only time Rarity’s interacted with them. As I said below, Rarity specifically wanted a friend to run the store. Those three are acquaintances at best. In addition, that gig was a one time special event; DJ PON-3 obviously does not have a club in Rarity4U. Also, where did you get the idea Rarity also leased the upper levels of the building? She only rented out the ground floor.

Even funnier, They went to another fashion show…

@Background Pony #B1C1  
That’s kind of the definition of “background pony,” which nobody is disputing that they are.
 
Now, you might be able to make a case that they were clients of DJ PON-3 rather than Rarity’s employees, in Pinkie’s idea (canonical and stated as such by Pinkie Pie in the script) of running the store as a combination boutique / dance club. But it’s unlikely. The store was still clearly Rarity’s. Which means DJ PON-3 at least was either Rarity’s employee (hired by Pinkie Pie), or Rarity’s client (hired by Pinkie Pie to perform for the boutique) or Rarity’s sublet tenant (which is a form of client, paying Rarity for space to run a dance club in her shop). Which in turn means the three dancers were either Rarity’s employees (hired by Pinkie Pie), DJ PON-3’s employees (hired to dance; and therefore Rarity’s sub-contracted employees), or DJ PON-3’s clients. But regardless of which they were, they were clearly (and stated outright by Pinkie Pie) intended to be part of the successful store concept.
 
Considering that it is also canonical to the episode (stated outright in the script by Rarity) that DJ PON-3 owned the club upstairs, it is highly unlikely that she was also talked into paying Rarity to use the space downstairs. You’re right that is technically my headcanon, but it would be monumentally stupid to assume DJ PON-3 would pay twice for two spaces in the same building, of which she can only use one at a time. So from that we can conclude, derived from show canon, that DJ PON-3 had to be running the club downstairs because she was an employee (likely contractor or volunteer rather than salary/hourly, but it doesn’t really matter) of Rarity, hired by Pinkie Pie to liven up the shop and make the music into a feature rather than an intrusion. So DJ PON-3 at least was not a client paying Rarity for the use of Rarity’s shop. She had to be an employee.
 
The security guard is clearly DJ PON-3’s employee, making him Rarity’s employee (sub-contractor) as well. All of this does not actually prove that the three dancers were also employees; they could have been clients (coming to see DJ PON-3). But having them arranged in a line, choreographed together, in an event that began on a cue from DJ PON-3, in which their dancing was a featured draw of attention for the clothes-shopping crowd, highlighted by spotlights coming up on them specifically as the rest of the shop dimmed, in marked contrast to their separate dancing upstairs, strongly indicates that Pinkie hired them to the store as well. And it shows beyond any shadow of a doubt, canonical and seen in the show, that as of the grand opening night Rarity at least knew them, and after realizing the paying customers liked having them in the shop (Diamond Cutter seemed to really like it; the guy has taste – yes, this part is headcanon), Rarity smiled about their presence and was happy having them there too. And it is therefore also canonical that in the shop concept, as arranged by Pinkie Pie for Rarity, they were intended to be a regular presence.
 
So no, it’s not “my headcanon.” It’s derived logically from the show canon, the only two pieces of speculation being that DJ PON-3 isn’t stupid enough to sublet space in Rarity’s shop when she’s already paying their thug landlord for space upstairs (which is hardly speculation); and that their arranged and spotlit dance performance wasn’t spontaneous but was planned to be a show (which also isn’t really speculation) given how it was lit off. So it’s headcanon whether they were paid or volunteer employees (and I don’t care nor did I state which it was), but it’s barely headcanon that Pinkie Pie employed them to dance for the store. It’s the most likely explanation for their presence.
 
So maybe Rarity did ask them (and/or DJ PON-3) to watch the store and they weren’t available; maybe they weren’t even available to ask; or maybe Rarity didn’t consider them capable of doing more than dancing there (in her interview she did call them “foals” who liked their music too loud; and assuming they’re part of DJ PON-3’s entourage, hiring a mute who’s usually also functionally deaf with her headphones drowning out everything around her to run a store would be a very questionable move on Rarity’s part too) and didn’t want to ask them. But if she didn’t ask them, this would be a very reasonable reaction to it.
 
Why she wouldn’t want Plaid Stripes running the shop alone (or helping her with the fashion show), that’s also not headcanon except in the most pedantic sense.

@Ferrotter  
No they dont ,they stay in the background and talk/Discuss to other clients,that’s your headcanon

@cloudkicker108  
And raccoons.

@Ferrotter  
Rarity stated in the episode that she specifically “wanted a friend” to look after her shop. Hence why all the individuals she talked to in the flashback were all ponies she knew well.

They were probably out elsewhere at the time.

@Background Pony #B1C1  
Club-goers who, like the raccoons, got jobs as greeters and entertainment in Rarity’s store.  
…………………………………VVV……………  

 

???  
They are club-goers