Mark your comp classes as By Invitation and only the kids you invite are eligible to register.

You can set a class to have mandatory and/or optional sessions in the week. The price is calculated automatically based on what the family chooses.

Perhaps you charge a fixed fee for choreography, or chalk. No problem, just add it to the class.

Set up your meets as open or by invite. Set the price, and keep track of who has registered and paid.