I had the same issue with my barracuda. I spent weeks going through the same things you have done until I discovered that my trans had a small leak around the neutral safety switch (on the trans) that allowed fluid to pool up in the connector on the neutral safety harness and was shorting causing a no-start condition, I cleaned the plug on the harness as well as the prongs on the switch. Cranked right up! Wouldn't hurt to check!