When I’ve switched races, it doesn’t show which battles I still need to complete - it appears as though they’re already done.
From my reading of the unlock system, it doesn’t matter which races you complete the missions with, but which difficulties you complete.
I think for the third race you need to do them all on hard, and for the fourth, them all on expert (meep!).
I could be wrong but that’s how I interpreted the unlock information.
Yup this is the case, although its shockingly badly explained in the game.
Ohhh! Okay. My bad! :3