tbf I think the only hard thing about it is how do u judge how many players are allowed in the tournament (e.g. per team), cause u cud have it like flying and dueling where u do it with a different tournament per thing (however I think this wud put too much stress on the arena team if the ladder system was done especially if they were often), you could also do it so anyone cud sign up with how many (tho this wud be kinda unfair but also mean that the tournaments cud be less often and even be done in a world cup sort of big style) or u cud just limit it to like 7 and say if u dont have 7 u cant join (but this wud be kinda sad as it wud leave out ppl with smaller friend groups and wud leave out people in friend groups larger than 7), idk, personally if it wud be done I wud prefer it to be done less often than flying or dueling to make it more of a cool thing. The final option of course is by doing it by house like in the books. Theres the way where you just let people in their house choose who they like in their house until they get a team (this wud be kinda dumb as it would leave even more people out and disconnect ppl) or just have it so its like the old tournaments where its like elimintion (but if the ladder system was in place this wud be even more work for the arena team)