Flying definitely stays. Default bodies are capable of whatever movement default bodies can do, be that walking or flying or anything else.
As far as biological "abilities" go, the line is kind of perforated, especially since there are plenty of canons that pass off exceptional abilities as having an innate, biological basis. The litmus test boils down to three questions:
1) Is this "biological ability" possible in reality, or does it rely on biological mechanics that don't fit the logic of Cosmographia's world?
2) Is this "biological ability" fair to other players?
3) Does having this "biological ability" interfere with the character adapting and coming to rely on their Gem powers?
Here's an example: if you're not familiar with Tokyo Ghoul, "ghouls" in that universe are humanoids who have a lot of special cells in them that allow them to, among other things, sprout a kind of tentacle weapon thing. Even though it's part of their fundamental biology, it fails all three questions; it relies on mechanics of "biology" that aren't realistic, it effectively gives characters an extra starting power, and it's something characters could fall back on instead of learning how to handle their default Gem weapon.
The second and third ones are mostly what we're concerned about. Cosmographia is a game about characters becoming Gems; characters aren't required to follow any specific development arc, but there should be a sense of them identifying more and more with their magic and less and less with their physical form, generally speaking, as the game goes on. As long as powers are played with in ways that fit the game's premise and respect other players (ie no powergaming), we're not going to nitpick too hard.
eeeee sasasul
As far as biological "abilities" go, the line is kind of perforated, especially since there are plenty of canons that pass off exceptional abilities as having an innate, biological basis. The litmus test boils down to three questions:
1) Is this "biological ability" possible in reality, or does it rely on biological mechanics that don't fit the logic of Cosmographia's world?
2) Is this "biological ability" fair to other players?
3) Does having this "biological ability" interfere with the character adapting and coming to rely on their Gem powers?
Here's an example: if you're not familiar with Tokyo Ghoul, "ghouls" in that universe are humanoids who have a lot of special cells in them that allow them to, among other things, sprout a kind of tentacle weapon thing. Even though it's part of their fundamental biology, it fails all three questions; it relies on mechanics of "biology" that aren't realistic, it effectively gives characters an extra starting power, and it's something characters could fall back on instead of learning how to handle their default Gem weapon.
The second and third ones are mostly what we're concerned about. Cosmographia is a game about characters becoming Gems; characters aren't required to follow any specific development arc, but there should be a sense of them identifying more and more with their magic and less and less with their physical form, generally speaking, as the game goes on. As long as powers are played with in ways that fit the game's premise and respect other players (ie no powergaming), we're not going to nitpick too hard.