So, I just went and tried to answer my own question about generating MultiRiffs for a track in my style.

I selected bars 5-8 of the Piano track and generated MultiRiffs. I opened the Audio window and dragged one of the MultyiRiffs into it. Then I undid the MultiRiff so my tracks would reappear.

Now I found that only the Multiriff bars would play where they were placed and everything else had been erased there! I tried to undo and step back and BIAB crashed.

Guys, it sure looks half-baked right now!