Should be able to get it running on the one ecu (don't need body or abs ecus), you don't need speedo.
As Roman said ethrottle and MAF are super important, ethrottle is in throttle body so no pedal needed.
The ecu controls the throttle from 0 to 100% however it allows manual pull on the cable from 0 to 25% for limp home mode. The ecu does the idle via the ethrottle. So manual control first, then ecu taking over not the other way around.
The other thing to check is fuel pressure as they don't like too low. Can't remember the exact number off the top of my head but over 50psi.
As Roman said try an OBD2 scanner. There's a guide on in a few places for setting up Torque on Android to connect (not automatic)
If you need any wiring diagrams, or pics of components feel free to pm me.