How can you be getting fuel, if the fuel pump is weak ?

You're either getting fuel injected into the engine or you are not.

Have you verified both fuel pressure and had direct confirmation fuel is being injected into the engine during cranking ?

No guesses.

You are getting good spark at all 4 cylinders, and at a time that would allow starting ?

Again...no guessing. Test and confirm.

Throwing parts at this, swapping stuff is a surefire way to make getting it running more difficult.