We have been to WDW 4 times on that weekend in the last few years because my kids have a teacher workday so it's a long weekend for us. The competition is at MGM, and MGM will be crowded with roaming packs of girls as well as their parents an chaperones. Their stage is the Indiana Jones stunt show so that attraction is closed.
Most of the teams stay at the All Stars, and those resorts are crowded and noisy. I wouldn't stay there at that time.
As for the other parks, the competition doesn't have much effect except you will find occasional packs of giggling girls near you while you wait in line.
We really enjoy going to WDW at this time because the parks are uncrowded (except for MGM).
Edited to add that you'll need ressies for dinner at Epcot because many of the parents wander over to Epcot to eat.