green screen tasks in reverse = problem

First time with green screen content, and I remembered it backwards....

I got all my green-screen clips with different camera angles assembled in the Project Library, synced to independently-recorded audio, added text etc, THEN proceeded to add the background content. This is not working, the background clips are covering the green screen clips. (I know, now, that I should have assmebled the background first THEN added the green screen clips on top....).

Is there any way to recover this without re-doing the whole thing (~40 clips, 24 min long)? I thought about rendering the existing project video now (with the green, without backgrounds), then starting another project with the assembled backgrounds in the Project Libary and green-screen video in the timeline, and adding it on top of the backgrounds as one long clip, would that work?