So I figured it out. I was able to just copy/paste the mapping from a single key, and paste it into a new instrument. I grabbed bits from various kits, and I'm in business.
However, despite each instrument being in it's own group, some of them I can map to other tracks, and a couple others I can't... they just go to MAIN despite me routing them to 5-6, and 9-10. Am I missing something, or could it be a bug? I noticed a lot of glitching in the mapping area as I was working, but in my case it's usually user error