If you meet the requirements to claim your daughter and her children as dependents (you can see the requirements below), then that would probably be your best bet.
Note that your daughter may need to file a "dependent" tax return to claim her income.
Regarding the refinance of your home, you can deduct any property taxes or prepaid mortgage interest as well as the normal housing items as long as you paid them.
The requirements to claim your daughter and her children as dependents are below:
https://ttlc.intuit.com/replies/3288503
