Since the new fireworks show called Wishes premiered last fall, it has been shown every single night. It is a wonderful show.
We've been several times around Columbus Day and have never found crowds to be too bad...some years they've been wonderfully sparse. This year we'll be there later in the month so we'll see.
You'll love the Polynesian. We've stayed there many times and even during the busiest times, it is a peaceful resort. The pool can get busy but there is another pool and three beaches to find some tranquility.