Ok I didn't read it all but the first things I would do is check for fuel pressure. You said your pump was working so you can probably rule that out. The next thing I would do Is pull all the spark plugs and lay them on the valve cover Have some one crank the motor you should see spark out of all 4 plugs.

Did you check your cam timing you said your belt was intact but is the timing on the little white mark on the crank pulley should line up with the arrow on the cover and the 2 lines on the cam pulley should be level with the head valve cover gasket surface.

Other then that you may try checking compression. Another dumb trick I use is placing a screw driver on the injectors and the handle end on my ear with some one cranking you should hear them clicking.

Have at it.