>>35943896You don't have to do any variants, you can just keep them as they are. If you're really hard into the whole "fossil Pokemon only have rock typings because of the resurrection process" idea, that's fine, just take away their rock typing and substitute something a little more fitting. Like Water/Bug Kabutops, pure Steel Bastiodon. Don't touch Relicanth's typing, though, that never changed.
More than anything, I'd give them different abilities.Maybe tweak their movesets and stats, just a bit. A Ramparados with decent speed, for example, Aurora Veil Aurorus, or just Archeops without Defeatist.