Questions about pony body types

[Mysterycat 27]

I have a few questions.

1. Why do most ponies have round faces and some have square faces? Some say that the mares have round faces and the stallions have square faces but is that true? I mean Zecora is a female with a square face and so are Celestia, Luna and Cadence but not Twilight or Flurry Heart. Also, some colts have round faces. Are colts born with round faces and they go square when they grow up?
2. Why are Flurry Heart's wings bigger than her body and is it because she's an Alicorn?
3. Speaking of wings, why are Bulk Biceps's wings smaller than the rest of his otherwise large body? (Like they're the same size as a foal's wings)
4. Why are Celestia, Luna and Cadence much taller and thinner than most other ponies?
5. Why are Big Mac, Shining Armour and the Cake parents taller and chubbier than most other ponies?
6. Why do adult pegasi fold their wings to their bodies but I've never seen a pegasus foal do that?

[ReverieRiver 526]

Okay, let's tackle this one at a time!

1. The general rule is that male ponies have square faces and the female ponies have round ones. Zecora and the alicorns are largely exceptions to the rule (Zecora's not a pony, and the alicorns are just different). As for colts having round faces, well... Think about how young boys usually have round faces, but then they usually gain a more square or chiseled look as they grow older, hit puberty, etc.
2. I would gander a guess that it is, indeed, because she is an alicorn. Maybe she'll grow into them? It's strange to think about, because we've never seen an alicorn foal before.
3. Bulk Biceps is... an odd one. It just basically looks like he developed the rest of his body, but not his wings. I don't know, I think his design is meant to be more jokey than anything else.
4. Because they're alicorns. It seems that alicorns are generally just bigger than most ponies, perhaps because they're more powerful or the fact that they're said to have traits of all three races combined. I feel like eventually (and I mean yeeeeears down the road), Twilight's build may change. She already seems a bit taller than her friends.
5. Well, Big Mac and Shining Armor are just big, strong ponies. That's just the way they are. Same goes for the others you mentioned, it's just the way they are. If anything, I'd love to see more variation in body types like this, gives them more character - but that would be an absolute pain to animate so many unique shapes, lol.
6. That is... actually an interesting question. Huh. Never noticed that.