No issues here at all with Final Cut Pro (10.3.4), its stable and has not crashed once.
" Fortunately I'm only looking at a single, pro bono, gig right now. need to color correct an hour or two of music video (split into songs, correct, save...), and technically I could use Premiere, which is running just fine under High Sierra. But I have correction and filters loaded up for FCP, so I want to figure this out, if possible."
You should not be using a beta version of Mac OS to perform production work. Beta software is for testing purposes, not for normal day to day use. Therfore use the current public release of Mac OS installed on your Mac, presumably Sierra.
Yep, having the same problem. I even deleted all my plugins and re-installed FCPX, same behavior. As soon as I try to import any media it crashes. At this point I've probably sent 150 crash reports to Apple because it now forces you to do so.
Definitely my bad for installing the GM candidate, but if this happnes with the actual GM I'm going to be PO'd. I need Final Cut working...