Found this and I gotta say I like em alot. Overall, they're much better than the models of Equestria Girls. I read your comment about the skin color thing, but one reason that was in order to avoid any potential conflicts from real life skin color (least that's what I've heard.)
Do like human Spike though, so awesome points for you
You ever think of updating or tweaking your designsof them a bit? Not sure what I'd add though probably a bit of things of skin differntial (Applejack is probably the tannest from all her farmwork and might look a bit muscular.) Beyond that, not sure though I'm not sure if Rarity would wear a dress like that on regular basis. It's certainly nice, but too big a risk it might get dirty XDD. Spike probably be a bit taller (Regarding age, it always seem to be the CMC were like 10-11, Spike 2 years older (12-13) and the girls being 16-17 (since they're still growing)
Then again, what do I know? Still, awesome job nonetheless. Keep drawing!