Can you get any deals with Harry Potter or any special deals involving Harry Potter. My daughter is a huge fan and we would like to do something extra for her

If you stay at one of the on site hotels you get to enter the Wizarding World of Harry Potter theme area an hour before the park normally opens.

I do not know of any deals. But there are some great souvenirs you can get there.... like wands, robes, house color scarfs, etc

Being a resort guest let's you in an hour earlier Your resort might have some more insight on obtaining something special going to both parks is a super experience on the train