Good day.
I actually haven't tested these two together, so I don't know 100% if they're compatible.
I think they should work together. This plugin replaces the entire attack skill formula with the one you set on a weapon, and if that should happen to contain a weapon proficiency in it, it should still resolve normally, as it's still in a damage formula.
If you use the option to conditionally replace part of a skill's damage formula with its weapon attack formula, it should still work the same way, as, it's still inside a damage formula and should still resolve normally.
I can't speak to whether it would work in reverse or not though, so keep that in mind.
~Ramza