Adding __cpp_lib_format_ranges for P2286 and P2585 sounds like a good idea.
P2508 and P2419 are minor (from the implementation perspective) changes so I think just bumping the __cpp_lib_format macro is fine.
For the record, I'm willing to accept Victor's expert assertion that these are both small enough that there's no reason to support separate implementation and that a single macro bump is good.