My best weather trips have always been late February thru April. I also love going in October for the Halloween party, but it has rained on me every single time. Last year I went in September and it was hotter than Hades, 10/10 do not recommend.
I have not stayed at any of those resorts, but I've heard that the All Stars Music family suites have 2 bathrooms which could help save some time and squabbling with multiple teens. Or keep one bathroom to yourself and make them all share the other!