MouseFest will be on the cruise most of this time period. They will be there the latter part. I just plan to avoid the parks they will be attending. The big meet is Saturday I believe- we'll be gone- but check the schedule for updates on Deb's site.
From what I've read about the cheerleaders, for the most part they stay at the all star resorts. There have been some pretty bad reports from years past about behavior there and being really loud. However, I have read reports of them being perfectly nice and quiet too. I just plan to stay at POFQ and hope too many don't stay at the moderates. I've read the crowds at the parks shouldn't be affected much b/c they are in practice and competition most of the time. I heard they may close MGM down early on a Friday or Saturday night for some sort of party.
Anyway, with proper planning I think it will be OK. I might reconsider my all star stay though. Try for a moderate- I'm hoping to get a good code through Disney visa or AP passes.