There are no rooms at POP that sleep five...unless one of your children is under 3. Then you can do a pack n' play/crib or bring a blow-up mattress.
If 3 or over, you would have to do 2 rooms at POP, with an adult "positioned" in each room and request connecting rooms(which is never a guarantee). None of the value resorts allow 5 people, unless you get a suite at music.
We are staying at POP in April with 5, but the ages of my children are 7, 5 and 2.