RE: Using Futaba 4YF for a buddy box.
I've used a 4YBF as a buddy box. You don't have to have any of the above in it, as the master radio supplies the power and does the transmitting- but you can also leave it in if you wish. Just don't turn the buddy box on, and also confirm correct operation when you hook it up.
That's cool that your wife flies![8D]