You've done a lot of things, most of them good ideas. I would put the starter back in, pull the plugs, and take the red lead off of the starter, extend it with a jumper to the pos. terminal of the battery. just tap it, the starter should fire over the motor with the plugs out. If this works, I would check the starter solenoid, but you already swapped that. I wouldn't bother with the start stop switch, since you heard the solenoid clicking when you pressed it, its good. with all the extra parts you have you should find the problem.