Welcome to Just Answer,
Have you checked power to the coils or fuel injectors, it is quite likely you are having a problem with the ASD relay.
Let me dig up some diagrams and I will give you a couple of quick test.
When you say it fires 1 time, does it start and run for a second or you get 1 spark. If the ASD does not see a RPM signal from the ECM. Are you checking power to the coil with the ignition on or while cranking? Do you have continuous power to the coil while cranking?
If you have power to the coil and lose it when you crank the motor this will create a spark. Please understand I cannot test anything myself I have to rely on your information. So if any of my questions seem stupid or obvious its because I need to establish a baseline, and I never assume anything, especially with a problem like this.
I understand you are probably frustated and have spent a lot of time and money on this. You have replaced most of the related components so it is most likely going to be a ground or wiring problem.
Let me no if you have any more info, also let me no if the coil stays powered while cranking.