Hey Bazzikaster,
I've been regularly making multicams for years and perfectly understand your problem, as I "force" myself to make everything (edit) on Resolve, even when it's not eased by design... like multicam. What I can say here in the beginning is that
the WF includes manual stuff as one of the first comment suggested, so if you need everything to be automated, you can stop reading here...
So fyi, my workflow includes Plural Eyes which syncs everything (any video and audio tracks) before, exports xml which is imported in Resolve. Then you have stacked video and audio tracks which is a point you may have come to by another way tahn plural eyes.
Now, as I also like to keep spared audio tracks on the TL, what I do is that I make a default multicam file in Resolve (my WF is to use markers) > I duplicate the stacked tracks TL > I put the multicam file on top of all and wipe the other video files only (since I have them yet in the multifile).
So I have the multicam AND the extra audio files on the TL.
I've sometimes open the multicam file and inserted the extra audio inside before closing it again with random success, so audio tracks out of it is enough for meHope it was clear enough