So.
The .45-70 cases were dry ( I had set the paper plates with them and the steel pins in front of a box fan for an hour or two), so I did a quick once-over on the primer pockets with my fancy electronical RCBS case prep thingamabob (only takes a few seconds per) and chucked them in the dry media tumbler. I did notice the cases felt kinda "draggy" on the fingers, almost as if there were a sort of dry film on them from the brass cleaner solution, even though I rinsed them quite well in cold water. I'm assuming the dry tumbling will fix that, it normally does.
As for the pins, there was no rust whatsoever and they dried just fine. Though it appears to be a major PITA, I'm pretty sure I lost not a one of the half million little pins. I put them back into the drum for storage. Bottom line is, there is not a hint of pitting and corrosion anywhere on the cases, inside or out. Once these cases are finished they should look as good (or better) than new. I'll keep this thread updated with pix and posts as I continue.