Of course the Kill switch will also actives the same starter interlocks (and engine temp light off), so we need to keep in mind this if you saw (or expect) damage to the right hand switch assy.
Brought my book to work so I could look at the schematics during lax minutes. What I see is there are 2 wires on the right multi switch associated with the interlocks. My Clymer is page 596 1999-2000 LT models reverse. Without measuring, I am going to make general assumptions for later testing that the GREEN+RED wire between the MFS and the ESO relay is V+ to the relay and is controlled possibly by the kill switch as a master control for the interlocks?
I don't know what logic is in the reverse controller but it must be a logical loop of the remaining interlocs with a path to ground being, side stand switch, reverse switch, neutral switch etc....
Assumption #2 With no +12V on the GREEN+RED with the key on, the entire interlock circuit is dead as the relay will never engage.
1: verify +12V is on the GREEN wire leading to the right MFS with key on. If no +12, ignition switch damage may be suspect however, load relief relay functions so assuming +12 is present but verify.
2. verify +12 on GREEN+RED wire with key on and kill switch in center position. Should vary with left and right position change. If no +12, right MFS is suspect.
3. If 1 and 2 are present, possible reverse controller damage as it looks like the rest of the interlocks pass through there. Verify interlock switches one at a time to make sure no damage there.
If by chance the GREEN+BROWN is supplying the +12 then the right MFS would be supplying the path to ground but since BMW uses BROWN for ground, I am assuming that the GREEN+BROWN is a path to ground and GREEN+RED is the positive voltage.
EDIT: It looks like the GREEN+BROWN also connects to the motronic relay so that is another one I need to pull apart to inspect. Also verify +12 on the GREEN+BLACK wire on the motronic socket.