I wouldn't move the trams to the taxiway until the opening day after the airport is full and aircraft are minimal.
The trams would yield to aircraft, of course. And change direction as the runway in use changes. Trams frequently stop for crossing aircraft now. What's the problem?
The lack of unauthorized persons is exactly the point Plenty of security scooters patrolling that area. Cars drive on the taxiway at my local federally funded airport by design (0s9). No other way for cars to access the hangers.
But yes, I wouldn't hold my breath waiting for the FAA to get any creative or common sense ideas.