@marriard -- My DD#3 played in an AAU organization structured like that. The organization had a practice facility with 4 courts. There were two practices during the week focused on team play. Kids had individual instruction on other days. On Sundays starting at noon, a bunch of other organizations would show up for "game day". There would be 30 or 40 teams involved. On game days, the younger kids would have a random coach, while the older kids would run the teams on their own. For national or regional tournaments, the organization would put together a team and assign a coach.18 teams? Seriously? I've coached TWO teams at a time and was was stretched to provide adequate attention to both. And I coached basketball - every kid plays the position she wants to play? How does that even work?
"Positions" in TB hoops are irrelevant. The teams play man-to-man, so the kids match up after every substitution. The teams run a motion offense with the post players regularly swinging to the 3 point line and perimeter players going to the blocks. About the only designated job is "ball handler" where a kid's assignment is to take the ball down the court.