Let me answer these questions for you!
To the first one: No, a character will not be adopted by any admin or player. The character, if a person leaves, will be put into the Archived board in case that person ever decides to return and wants to continue to play it.
The second one: It is your race, your personal race, others may play it, and yes if you leave, you can take it with you, and request that it gets removed if you leave.
It all depends on the Gryphon type, is it an actual gryphon, can it turn into a person, is it half person, and that sort of thing. As for roles, you can choose whatever you want your character to be, whether it's a hunter for a village, a mercenary, a healer, any sort of role you want it to fit.