I can only add this:
The last weekend in April into the first weekend in May is USUALLY a big weekend for All Star cheerleading at Disney. worlds is usually the last weekend of April and Summit is has been the first full weekend in May.
While the athletes spend a lot of time at ESPN WWoS, there is usually the Sunday night when one park closes early for a ticket only event for athletes. For Summit it was HS last year and again this year. Not sure about Worlds.
If you are planning to stay at a value or mod resort, they will be very packed. This year for Worlds and Summit, the package deals are for Pop, All Star, and CBR. At this time, Summit has sold out of all their rooms and thereare still teams to be added to the competition next weekend if they win an invitation. Meaning, those teams will spill into other resorts. I'll add - My daughter is an All Star and we are staying at Animal Kingdom Lodge.