So, the word so far is... motor sucked up water, and blew the rear main. The block is junk and will have to be replaced. Sounds like insurance is going to cover it
Better news is (so far) the insurance company hasn't been able to find a used Hemi with less milage than mine, so they'll be ordering a new long block from Chrysler to replace it with. Seats and carpet and padding have been removed to dry out. I'll be avoiding any future water crossings (at least until the snorkel is in place)