Speaking from personal experience,,
Yes, a B&M tail light will work fine with a vintage dynohub, and any type of headlight.
Yes, a reflectalight led bulb will work in vintage headlights and be an improvement over an incandesant bulb, but not comparable to modern dyno lights. ok for being seen, but barely functional for seeing.
I have this $23 light and highly recommend it, at 40 lux its much brighter than vintage lights with either type of bulb, has a built in standlight, and state of the art optics like B&M lights.
https://en.hollandbikeshop.com/advan...eywords=356335