Help choosing sander to rent from Home Depot

I have a 160sf sunroom that I'd like to refinish the floor. The floor is not exposed to rain but it is very humid in the summers. The wood is cupped in some spots, I tried to show it in the pictures but it doesn't really show up that well. The worst cupping is probably 1/16"on the edges. I was going to rent a floor sander from Home Depot to sand it and I'm wondering if I should get the drum sander or would the deck and floor sand work? I also have a belt sander and a 6" handheld orbital but I thought the handheld would take too long. Any advice on which would work best for this application? Also, once I sand and apply stain should I put any sort of urethane or anything to seal it?