Does the IAC power come from the battery?, reason I ask, car would not start unless in neutral with gas constantly provided to keep the rpm's above 1k, until you put in into drive or rev. Then would run fine even after putting it back in park. Next day I drive it starting it this way and then no power anything, stranded in a parking lot. Replaced a battery and a negative cable end (shorting). Now the car is back to 'normal', no problems with starting. Am I just setting myself up to fail again or should I count this one off as the gremlins left.

No I think the battery cable was deffinately the problem - there are many people that have bad IAC like problem and say cleaning or replacing the battery cables or cleaning the battery post helped.