With regard to "no one is allowed into the house" rule: I hope no one needs to use the bathroom, and I REALLY hope it doesn't rain!
Alcohol rule: If this is an all-family event, I think it's fair if she makes whatever rules she wants, for whatever reason. If she doesn't want alcohol on the premises, it's fair to make that rule.
Money: Actually, this bothered me more than the other rules. Are the "leftover" funds normally left for the end-of-the-year party? If it's something she decided to do "just because," that's not cool.
She should have just invited the team for the party. It will already have about 15 kids, plus however many coaches. That could be about 20 people, give or take a few. That can be an awful lot of people!