What all has to be unhooked from the body to remove the engine and transmission through the bottom?

Brake Lines, wiring harness, Steering Column, ?

 

The things you listed plus the K-member, driveshaft, trans cooler lines, coolant hoses, trans cross member, exhaust, AC system (at least at the firewall, not dismantle it all), brake lines from the master cylinder, struts (if you drop the motor onto the k-member on the floor). Can't think of anything else.