[Kitalpha Hart]

Gaia's also really frickin old and tends to be slow about changes
And fixes
And updates

Let's see, of the sites I'm on...
Windlyn the base is neutral, the clothes you choose determine the "gender", using the word loosely, of the avi
KofK I haven't tried to change so I don't know. Male and female bases do have some differences in items, but I'd say about 90% of items tend to be the same. The site's avis are also bust shots the chest on the females aren't very large
Flight Rising is dragons. Easily changed, so long that specific derg is in your lair
Marapets is a pain to do anything. You need to pay a fee to change your outfit's colors. Don't have that color unlocked? Buy eggs and hope you get it. The base? Yeah I haven't even tried that
Voltra has the option in the avi creator, so you can change it with every outfit
Pantheon you can choose in the same place as Voltra
And here, well, y'all know the answer already

As for sites I've left, well, it's been so long I don't actually remember if it's possible lol