Woo, this is a tricky one.

All in all, I think I would keep a lot the same - one of the strengths of Discord and he way the SHL utilizes it, is that there is autonomy within the channels on a team by team basis. It gives each locker room a different feel to it, and allows teams to cultivate what kind of team environment they want depending on the variety and content of the channels there are. 

The major change I would look into would be a flair or some kind of set tag that indicates the user's player and team(s) they currently represent. The username as it is can be quite fluid, and it is difficult (especially for mobile users) to tell who is who on any given day. This change would also help new members get acquainted with experienced players, and keep track of who is who despite name or avatar changes without needing to hover to see the discord tag. This would obviously only need to be a change for the general SHL and SMJHL channels, as the team channels shouldn't need to tell you what team they are on (although it might help for alumni, but most team chats have coloured usernames to distinguish that.)