Jumper Cables Reversed

That's a tough one.  I know from experience that if you run a battery down to really dead, you can then reverse the jumper cables and re-charge it in reverse (positive post becomes negative and vice versa).  We used to do that for Ferguson tractors all the time - they were "Positive Earth" machines.

Since the battery was somewhat charged and you only had the cables connected for a minute or two, I suspect that you did no permanent damage.  Both alternators are protected from reversed polarity by their internal diodes, and the rest of the circuits in the charging car also should have some protection from people who might do just what you did, only in a blinding snowstorm at 2AM in Michigan or something.

Bear in mind, though, that Power is not my forté - I'm better with circuits under 3 volts - but I've done and seen some weird stuff in cars and trucks over the years and what you did is comparatively tame.  If the radio and A/C work in the charging car (and maybe drive-by-wire, if you have that) with no idiot lights coming on on either car, then you're probably OK.

Kinda makes you sweat about it, though, doesn't it?

Probably not.