Some things to note before you ask a question:
Character Appearance /Gender:
You can make your own characters whatever gender you want. Make the Queen of Spades a male and I won't say a thing.
As for Chains with animal roles (Dormouse, White Rabbit, Cheshire Cat, Caterpillar etc etc)
Your character can look like anything you want to, I personally would prefer humans. (because lets admit it, a talking dormouse or rabbit would be too hilarious and adorable and get people all distracted - at least me, I don't know about others xD) They turn into animal forms only when they themselves (and not their Contractors) are using their power as a Chain. If you want to have the ability to transform outside that, its your prerogative! The role you have won't decide your appearance.
Chain-related Stuff:
'Chain' basically means all Wonderlanders with special powers, who have the power to make Contracts.
All Chains are not bound to make a Contract with an Alice Candidate. The ones mentioned in the Character List (located in the Introduction to the actual RP) who are exempt from this are the two Queens, Knave of Hearts and the White Rabbit. But the Queen of Hearts makes one anyway.
Chains other than those mentioned in the CL can exist, but they can't make contracts with an Alice candidate,
This one's for player-made Chains and the Chains who are exempted from making Contracts with an Alice Candidate (White Rabbit, Knave of Hearts and the two Queens):
However, if you want a Contractor and can find a human other than an Alice candidate, that's actually fine. You just have to make it look plausible because not everyone can enter Wonderland.
A Chain can forge multiple Contracts ( but not Contracts with multiple Alice candidates), but they lose some of their own life force while making each Contract, and Chains with multiple Contractors are sensitive to every pain of their Contractor.
If you have any questions outside these, feel free to ask! I don't bite... well, not usually, anyway! And don't feel shy about asking, questions are always good. It means you care enough to find out.