Hi Martin!
First, I appreciate your carefully written and well structured post … no reason not to stay with you.
You’re probably already too far gone to change approach, but, my workaround would probably be the simple way:
1. Create a sequence for each pair of host/subject clips.
2. Put the host clip on track 1, and the subject clip on track 2
3. Synchronize the two clips.
4. Razor blade between questions / parts, throw away unwanted.
5. Where you want to see the host, disable visibility of the subject clip-bit sitting on track 2.
6. Reorder, delete unwanted or put it at the end.
7. Copy the bits you want from the different sequences to a new master sequences ..
Well … maybe it’s too easy, but it looks better then a not working multiclipversion …
Gilbert