bare minimum need to start hemi 5.7 out of car?

It will run without 02 sensors just in closed loop. crank/cam signals, fuel injectors, coils, throttle is about all you truly need plugged in to make it fire. A stock truck pump stuck in a 5 gallon pale running a line to the fuel rail will work. The stock pumps have a built in fuel pressure regulator on the top (fuel outlet). So head to a salvage yard, drop a tank, grab the line and pump and head home.

FYI I think the pump from a 4.7 or even 318 should provide the right pressure range. If I remember right. I had compared my service manuals and my durango pump (4.7) is rated to provide the pressure I need for my 03 hemi.

This is what I did for testing. If you can, also get the pigtail that plugs into the pump for easier wiring.

If the engine has been sitting for a while pull the fuel rail and injectors apart and clean the fuel rail. When I first tried to fire mine the fuel rail had corroded some and debris instantly plugged the injectors so it wouldn't fire.