IMNC's scale of MLP anthropomorphism:

Stage 0: A normal MLP-verse pony

Stage 1. quadrupedal -> bipedal; teats -> breasts in primate-like position, as you can't really breastfeed well if you're bipedal and have teats where they are on a pony; barrel stomach -> primate-like stomach, as barrels are because of the weight distribution in being quadrupedal

Stage 2: forehooves -> human-hands (in the show, hooves can do way too many things that they shouldn't be able to. Then again, their society couldn't really exist without that ability. Anyway, hands are really good for things that hooves can't do even with MLP hooves. Fingers are really nice for... lots of things.)

Stage 3: hindhooves -> human-like feet

Stage 4: fur coat -> skin the color of their former coat; muzzle -> human-shaped head; mane -> human hair pattern

Stage 5: skin the color of their former coat -> human skin color

Stage 6: Everything is human-like except for the possibility of horns and/or wings on relevant subspecies

Stage 7: Nothing non-human (outside of anime hair and eye color)

The suffixes "e", for "pony-ears", and "t", for tail can be applied to Stages 4&5. For example, a Stage 4et unicorn would appear mostly human, but with colored skin, a horn, a tail the color of the original tail color, and instead of human ears, fuzzy pony ears on the top of its head with the same color as either the original coat. I guess the only thing left out is whether the cock is pony-like or human-like. I'd like a way to designate that, since it could be either at any stage except 0 because of personal fetishes or turn-offs, but I also don't want the scale to be NSFW by default. I guess 'p' for 'pony' and 'h' for human, where relevant.