Such a cuuute concept and pics!! I can see why you matched them this way.
I think I'd see the ponies as combinations of the following princesses (using the "official ten," plus Kida for Dash since that does make some sense):
Rainbow Dash: Ariel/Kida/Mulan/Pocahontas/Jasmine (she and AJ or possibly even Twi or Rarity could have some Esmeralda or Meg thrown in, if considering other heroines) Applejack: Pocahontas/Tiana/Belle/Mulan Twilight Sparkle: Belle/Mulan Pinkie Pie: Rapunzel/Ariel/Mulan Fluttershy: Snow White/Cinderella Rarity: Aurora/Jasmine
Interestingly, My Little Pony: Friendship is Magic succeeded at what The Disney Princesses were trying to do, prove that there are many ways to be a girl. The Disney Princesses failed because the sheer femininity of their concept and merchandising overpowered that message. Plus, the princesses themselves weren't designed to be together. Every single member of the Mane 6 was made specifically for this show, and while there is definitely femininity here, it doesn't totally overpower everything else.