If its not part of the airplane its luggage.
Field box better be as little as possible, as fewer items as possible to carry to the flight line.
If you get the battery pack that attaches to the starter you don’t need the power panel nor the battery nor the field box….
The electric fuel pumps are pretty much useless better to have a manual crank pump and use a rechargeable glow starter.
Sure I have ton of helpful stuff in my trunk.

Alex