So I am just taking a gander around Universe Mode and I noticed that you can control each team while the commissioner. I am just wondering something now- I made a bunch of coaches for the game. Do I have to keep my coaches or delete them and only just control that one coach for the Universe (Or just play as the commissioner)?

You can do the acttions for any coach you created when you were creating your Universe Mode association. For many of the activities, you do the action for each coach and then there will be a link to send the action you took to the commissioner. You then do that for each coach and go back to the commissioner screen and click advance and those actions will be performed. Of course, if you want to sim any of the actions for all the coaches, you can go to OPTIONS and click on whatever aspect you want the AI to do.

I tried to do one of the actions for a team that I have not assigned a coach and it let me do that specific action.