oh good lord another guy who asks opinions and ignores them, there are tests to be performed before you just start replacing **** randomly. leaking return lines will not cause a no fire when warm but rather it should start better warm than cold. not sure on compression numbers. search google for intellidog and his site has fuel pressure and volume specs to test lift pump. The only thing I know of that will cause the issues you are speaking of is a worn or trashed ip or maybe timing. If these issues did not occur just after an ip replacement or major timing adjustment we have almost certainly eliminated timing.
while I am replacing the ip I would get those dps ******* out of there or at least have them tested for spray pattern and pressure. pattern should have fine atomization and pressure should be approx 1850 with all injectors being within about 5% of each other.
Lastly since no one has jumped you about it yet, I will. Rolling coal is not cool and will not net you anything but lower mileage, carbon buildup, and adding a bad name and further emissions standards to diesel vehicles. Honestly I can roll more coal than most on here with the ip up 4 flats and being na but my truck rarely ever spits any noticeable smoke because I have found personally it does nothing for me.