My qtns is if i file rcr case and
if i win rcr case, and then too she refuse to return my home, wht will happen :
Nothing will happen, the court cannot force to cohabit with you against her wishes. You will become eligible to file divorce case against her after years of RCR decree in your favor and she is not returning to the matrimonial home even after the decree went against her.
1 does she has right to file divorce and marry another man
It is her right and decision, no one has any right to interfere in her decision, however what will be the ground for divorce?
2 does she has right to demand maintainance?
Yes, she can file a petition seeking maintenance in the capacity of wife.
Basically your case appears to be a voidable marriage because the relationship comes under prohibitory relationship. It is almost your brother's daughter.