holy crap I actually figured it out after like a freaking decade, I've been annoyed by this for so long, so literally all it is, is mcheli utilizes the /scoreboard commands to manage teams. For some reason when you create a team with the mcheli menu, it didn't seem to show up in the "/scoreboard teams list" for me, but if you create the team with the /scoreboard commands, it shows up on the mcheli menu. So basically just use that command to manage teams. You can create and delete teams and add and remove players freely finally. Hope I fixed everyone's issue here.