It is certainly possible. The only other person I have heard suggested for the reyna of Hearts is Regina's mom, and that has not been confirmed.
The only other character I have thought of for the nurse is one of the good mga engkanto from sleeping beauty (she even has a similar hair style). The problem with that is that she doesnt seem very good, but maybe they changed it.
edit: after I posted this I thought about it, and she could also be Cinderella's stepmother!
If that is the case (which it might be) it would certainly explain how Jefferson knew about Belle in the first place...maybe Regina captured her and sent her to Wonderland before the curse...omigosh! What if Belle is also Alice? That would be really cool!
