i am just a "user", but i have had my username changed just a few weeks ago by using the online support form:
Please contact support with any requests to change your username. Include your current username and the username you would like to change to.
support.chaturbate.com
my follower count stayed the same (the amount of ppl that are follwing me) even if i am not a model myself, i still have had XX followers (models that i have tipped in the past) and they are still listed after my namechange as followers, and also the amount of the models i am following also stayed the same.
so i guess when they change the username, they will change it EVERYWHERE, so everything should work and be the same as before, just with a new name.
(but i can not tell if its working also with the club members or not, because i have none
but maybe wait for another more qualified answer from somebody else.