Part of the problem is that you have multiple people working on your car, yet no one truly *fixing* the root cause of the stalling. Intermittent problems are a mechanic's worst nightmare which is why most of them will replace a part and send you down the road, hoping their best educated guess actually fixed something.
So let's start with the basics. Can you connect a fuel pressure gauge to the engine and check the actual pressure? The pump might be new but that does not mean the fuel pressure is getting to the engine.
This would be my starting point.
BILL