The worst-case scenario I can imagine is the need to modify an enlarger in some way to take bulbs it wasn't designed to use -- say, pulling out the bulb fixture and replacing it with something else, perhaps in combination with an extra transformer or control panel. Chances are there'll be simpler solutions for most enlargers, though.
No need. There are already red and amber LED bulbs that screw into conventional tungsten sockets. Perhaps if your safelight uses some bizarre socket you'd need to do something weird, but the safelights I've seen (in the US) use conventional Edison sockets, the same as most household lights. Any bulb intended for conventional light fixtures will therefore fit, and of course the bulbs are being and will be designed to fit these fixtures. Maybe in 100 years homes will be designed with different fixtures in mind, but until then getting a working LED safelight will be easy.