Hi, Heather! If you plan on spending a majority of your time at Magic Kingdom, then the
Polynesian is going to be closer than
Port Orleans French Quarter. I looked at the Unofficial Guide to Disney world that lists approximate commute times to parks from resorts. If you take the bus from Port Orleans French Quarter, you can count on about a 22-32 minute commute. From Polynesian, about a 10-13 minute monorail trip.
So the question becomes is it worth the extra money to go from a Moderate Hotel to a Deluxe if your only factor is about 15 minutes commuting each way? Well, I love the Polynesian, it is one of my favorites. I also love POFQ, but it is nice getting your breakfast at Polynesian, sitting at the outdoor seating area and looking over at Cinderella Castle!! (And the pool is fabulous!)
The rooms at Polynesian do sleep 5 quite comfortably, so you might be able to save by getting just one room here. But it is up to you, you'll have to weigh the pros and cons!
Staying at the Beach Club will put you within a 15 minute walk to Epcot, but you will have about a 25 minute bus ride to Magic Kingdom.
So many decisions, but I don't think you can go wrong with whatever you choose! Good Luck!