Can commissioners add players to teams as the draft happens?
Yes! The easiest way to do this and preserve the draft results for historical reference is to schedule and run a live draft. At the start of the draft, the commish can select the pause button and then use Commish Draft to enter every pick. (The draft can be kept on pause the entire time so that there's no timer feature to worry about.)
Note: To get familiar with the pause and Commish Draft features in advance of the draft, the commish should try out a mock draft. The link to the mock draft is located on the Draft page, below the draft board in the Pre-Draft Checklist section of our desktop site.