Headcanons in a nutshell:Twilight is bottom heavy and has a sorta bumped snout. AJ is the chubbiest and shortest, and her stubby nose and gap between her teeth are her most prominent features. Dash is very thin and lanky and likes to change her hair a lot, ranging from long and in a ponytail to short and shaved on one side. Rarity is a petite pony with very sleek, roundish features and has a much longer tail than most unicorns. Pinkie Pie is rather large (both tall and a balance between muscly and chubby) compared to the others except Fluttershy and even the fur near her hooves is a bit curly. Fluttershy is openly MtF and is half earth pony half pegasus, making her naturally larger than most other pegasi.  
Also, I want to credit for the idea of pegasi (and alicorns) having tailfeathers as well as unicorns (and alicorns) having cloven hooves and lion-esque tails. (Even though it is just from mythology, the inspiration came from her gorgeous art.)  
Please don’t copy or trace this. It’s my art and it belongs to me, thank you.