Welcome to the Forum!
Although you spelled out the trucks details in your first post, itís important to have all that 411 in a signature line (see User Control Panel) so readers know all the truckís basics in each post and donít have to refer back.
Also, you seemquite wise in the ways of LB7ís and the tests you have performed are informative.
A couple of observations:
ďwhile cranking, rail pressure is 1400kPa / 74psi MaxĒ
That kind of rail pressure at cranking will simply not do and you need somewhere around 5,000 psi to wake up the FICM and get the injectors on line.
Iím too lazy to look up total return rate specs, but the test you did seems to indicate the internal ball and seat in the injector return circuits are working properly. Double check me on that, since failure of even one injector return circuit will certainly blow off all your rail pressure.
ďNot making oilĒ is obviously good too, since that rules out leakage around the return plumbing. Cracked injector bodies can also blow off rail pressure, but most of those old Bosch sticks are long out of service. Did you do a ďpaper towel testĒ to make sure no fuel in the oil?
For diagnosing low rail pressure, search is your friend and donít hesitate to use a search engine, which Iíve sometimes found to even uncover posts here on the Forum that didnít come up under our own Forum search, or were too buried in multiple key word hits to sort through.
Frankly, Iím more concerned about the multiple electrical symptoms that have presented, and would make every effort to address those before even attacking the no-start. While I canít see a connection between low rail pressure (which is pretty much a mechanical issue involving various elements of the fuel delivery system) there may be electrical interactions Iím not of that can cause low RP. Just canít recall reading of any.
Quite often, multiple seemingly unrelated electrical issues can be traced back to a single sketchy ground, cable or connector and Iíd spend time using the time-tested ďwiggleĒ system, along with a careful visual inspection to narrow your search.
And regarding the key fob, unless Iím mistaken, ours only accesses the panic alarm and doors, and unless there is some connection to an anti-theft function, I donít see the key itself being part of the problem.
And WOW, does your MiL know of your low opinion of her?
You seem to be a smart guy and have checked all the ďlow hanging fruitĒ boxes, and Iím confident you will solve this problem.