Whoooops I completely forgot about the retry button that appears when you fail a mission. I'll definitely test that out, I assume it works totally fine.
I may be trying to gamify it a bit too much, as I was supplying an option to return to a previous mission (ie: fail mission three, return to mission two to attempt to beat it "better" so that when you re-enter mission three you have more repair resources or less destroyed systems, for example). In that scenario, which I admit is pretty specific, currently it wouldn't be returning the lancers to the state they were at when they first entered mission two, but rather their current state after failing mission three.
It's totally not important, and way easier for me to rework what I've done then to add a whole trigger, but I do appreciate the support!