Dunno if this has been done before…. but here’s Firefly and Surprise… Genderswapped!  
Rule 63 is my personal favorite rule, unlike a certain rule that comes after 33.
 
In case you didn’t know, Fire Fly and Surprise were the original designs of Rainbow Dash and Pinkie Pie, respectively. However, hasbro couldn’t copyright the names, so Lauren Faust had to change their names and designs into their current incarnations, and that’s it.
 
Genderbent, I’ve named them:  
Lightening Buzz : Sounds like Lightning Bug, an alternate name for the insect fire fly, plus the “Lightning” part is quite fitting, as is “Buzz”  
and…  
Extravaganzo : Okay, less proud of this name, but it still sounds pretty Surprise-ey, eh?
 
I changed their designs slightly and didn’t go for completely show-accurate looks because ’m a rebel like that