Yes, the unloader/destroke could cause intermittent harder starting. Wiggle the steering wheel as in post #9 to determine if the hydraulic pump is not destroking and causing the hard cranking.
You could have multiple problems going on, could be all electrical related, or could be a fuel issue along with mechanical starter issues.
Hard starting is tough to figure out with all you have going on, go back through the suggestions and tell us what's been done and what's not been done.
The stalling after running is easier, either you're running out of fuel because of the blockages that you know you had, and are probably still dealing with. Or you're losing voltage to the injection pump, or the injection pump solenoid is failing. Most likely you have garbage in the tank plugging filters again, combined with possible cracked hoses. Fix that first, then worry about the electrical if it still stalls with a clean fuel system. One way to diagnose the stalling is to add a LED light on the dash fed back from the injection pump terminal, so the light confirms power to the injection pump, and/or a fuel pressure gauge teed into the supply to the injection pump and run to the dash so you can see how the fuel pressure holds up under load, and have warning before a stall. Neither of these is needed if you clean the fuel system and it stops stalling.
You could have multiple problems going on, could be all electrical related, or could be a fuel issue along with mechanical starter issues.
Hard starting is tough to figure out with all you have going on, go back through the suggestions and tell us what's been done and what's not been done.
The stalling after running is easier, either you're running out of fuel because of the blockages that you know you had, and are probably still dealing with. Or you're losing voltage to the injection pump, or the injection pump solenoid is failing. Most likely you have garbage in the tank plugging filters again, combined with possible cracked hoses. Fix that first, then worry about the electrical if it still stalls with a clean fuel system. One way to diagnose the stalling is to add a LED light on the dash fed back from the injection pump terminal, so the light confirms power to the injection pump, and/or a fuel pressure gauge teed into the supply to the injection pump and run to the dash so you can see how the fuel pressure holds up under load, and have warning before a stall. Neither of these is needed if you clean the fuel system and it stops stalling.