@Daneasaur  
King Sombrero could never be Asgore, he’s not really someone you can feel empathy for, what with him being a two dimentional character.
 
Speaking of which, @VermiIIion  
I think I’ve cracked it, Gaster could be Apple Jack; She’s completely missing despite how she’s supposed to be part of the main cast, but instead, is just a background pony…
 
I believe in || Engineer Jack||

@The CLaUD  
Yeah, Sunset would probably be good for Asriel/Flowey. Maybe Discord could be WD Gaster? I really can’t see him as Sans because Sans is lazy/depressed while Discord is a happy god of chaos.
 
Maybe Starlight could be Chara? Chara isn’t the player.

@The CLaUD  
Frisk, the canon frisk, was deemed best as Spike since he can “mold” into kind or cruel depending on outside influences, but ALSO prefers NOT to fight.
 
Celestia was Toriel
 
Good King Sombra was Asgore
 
Starlight Glimmer is Asriel
 
Trixie is Papyrus
 
Discord is Sans
 
Twilight is Alphys
 
RD is Undyne
 
Fluttershy is Napstablook
 
Rarity is Mettaton
 
Scootaloo is Monster Kid
 
Those were the ones covered. I believe Muffet was left as is because she works in either situation. temmie was a toss up between Pinkie Pie or Derpy.
 
And no, we didn’t have a clear cut AJ picked out.

@VermiIIion  
I think frisk/chara would have to be just frisk/chara, since they’re supposed to be the player anyway, they’re not meant to be characters, they’re meant to be you… so frisk’d probbably be anon at the very least… also, I agree about lulu&tia, but not so sure about discord as flowey, he’s not really homocidal enough, so I have to agree with the earlier comment that he’d be better suited fr sans. I think maybe one of the villans, like sunset could be flowey, cause’ you need to hate them as the bad guy, but forgive them as the reformed version (Eg Asriel)
 
Jesus, I need to slow down… #WarAndPeaceEatYourHeartOut

@The CLaUD  
Luna as Toriel. (Sweet, kind, but strict)  
Celestia as Asgore. (Gentle, a bit too nice, underestimated)  
Maybe Discord as Asriel? He’d really be a good Flowey.
 
Not sure who Applejack would be. Also unsure who Chara/Frisk would be.

@ZeroSpawn47  
yes, I know, but canon and fanon get very blurry in my head sometimes.

@The CLaUD  
His name is Bulk Biceps.

@Background Pony #7E45  

 
Yes!
 
>Dweebs.  
>Dweebs!  
>DWEEBS!

@The CLaUD  
Right? Not many could fill mad dummy…

@The CLaUD
 
Limestone or Gilda!

@Trixie1995  
I don’t think so, at first I was thinking maybe snowflake, but I don’t think he’s motivated enough for that… he’d be better suited for Aaron

@The CLaUD  
Screwball? lol.

@Trixie1995  
that was exactly my point.  
flutters couldn’t be the “royal scientist”, but twi absolutely could
 
either way, I think we can all agree, Steven Magnet should be Onion-San
 
_{^{but, who do we think would be the mad dummy? Discuss.}}

@VermiIIion  
Oh yeah… That was true. But… The bad thing is that well… Fluttershy building robots?…

@Trixie1995  
But she isn’t, and Fluttershy is the only one who’s shown to have interest in anime, if you don’t remember those cardboard cut out ghosts from the Halloween episode. Plus Fluttershy has more otaku traits than Twilight, being incredible shy, with high anxiety and has difficulty socially. Twilight is just a bookworm.

@Daneasaur  
Good point. Lol.

@Trixie1995  
Don’t forget LAZY.
 
Never does anything despite all his power and would need to be pushed to the brink in order to do so.

@Daneasaur  
Teleports, sees multiple timelines… Sure. I’d go for that.

@That One Guy  
Because RD has to be Undyne.
 
Also, No way can Pinkie be sans.
 
It has to be Discord

@VermiIIion  
Twilight is more likely to be otaku than fluttershy. :3

@That One Guy  
Except Papyrus and Trixie have the moments where they don’t have their days. (And we all love to see both of them get angry over things even if it’s not canon/related ) which pairs with their sassy third-person narcissism. The only difference is that Trixie’s an antangonist that doesn’t do stuffs right and she’s redeemed.
 
Papyrus is pretty much Trixie with RD’s loyalty and a huge care of friendship to the player. (AKA what Trixie would have been if hypothetically she were a main/side character ).

@VermiIIion  
Flutters isn’t smart enough to be alphys. Do you think she could invent a cellphone with a jetpack built in? besides, everyone knows twi is the biggest weeb.

@The CLaUD  
Wouldn’t Fluttershy be a good Alphys? I mean, the animus…

Okay people, let’s do this; Rarity is mettaton  
twi is alphys  
fluttershy is napstablook  
Continue;

@PonyPon  
Shining armour is greater dog confirmed.