Just to clarify, you don't register your drone with the FCC. DJI already has approval for the frequencies used by that and most, if not all, its other drones. If DJI is added to the "Covered List," they would no longer be permitted to register...
I will have a strobe light on the main drone that I will be deploying for winter flying - Air 3S. I recently acquired a new-to-me DJI Flip, but I likely won't put the light on that, or my Mini 4K. I will look into reflective tape, thanks!
You've covered pretty much all the bases already, the only thing I'd add is... lens fogging.
With the smaller drones in particular, you can end up with condensation between the actual lens element and the 'glass' fitted into the front part of...