Had a vehicle in the past where the long crank issue was caused by leak down in the fuel system, i.e., there was leak that caused the injector system not to hold pressure particularly overnight. Once the engine starts can you shut it down and then restart it immediately? If so, then look for a pressure leak somewhere in the system. It probably isn't something that you can find visually. You may need to put a pressure gauge in the line and then check the pressure in various situations. It may be an injector seal.

Jim Paget
88 YJ with a few changes