I'm not sure if I have missed something here but if you are talking about building a core/hybrid I would have thought the answers would be;
(1) Yes, you should be able to control the UI via Bluetooth mouse/keyboard. I used a Bluetooth Keyboard (with a pad) for a while before I got a Gyro. It is a little clumsy compared with a proper gyro remote or touch screen orbiter (you need to press keys like F6, F7 etc to get some menus) but it should work.
(2) As I think Thom is suggesting the follow-me won't work. You would probably need to repair the devices each time you want to switch from the Hybrid to an MD... The Gyration Remote GYR3101US is a cheap alternative to the Fiire Chief but keep in mind it doesn't work out of the box and you won't get all the keys mapped like with the Fiire remote.
Cheers,
WR.