Match Making Rating Budget (MMR Budget) is a simple way to balance teams. Similar systems are used in professional sports such as Hockey where all teams have a 'salary budget' where they cannot spend more than the money allocated to recruit players to their teams, insuring that the games stay entertaining and that the overall skill of the player pool grows uniformly.
Since this is a league tailored for entertainment, and also because we aren't being paid, we'll be using MMR as our currency instead of actual money. Each streamer will be given a max MMR which they will use to 'purchase' players based on their highest MMR.