[v8volvo]

Doesn't sound like a fuel system issue. This reads like a text book case of some dead GPs. Even if you replaced them, a sticking relay or other issues could have given a short life, their recent replacement doesn't rule them out, particularly considering the way these symptoms sound.

I would start by testing continuity of the plugs in the engine now. You can do a partial test in a couple of minutes, testing the rear two takes much longer, but by removing the bus from the front four, you can check each of them individually. Then, check the resistance of the terminal leading to the part of the rear bus that is still connected to the #5 and #6 plugs. This will only give you real information if you find an open circuit there, indicating two dead plugs -- if you find continuity then you have at least one live plug or maybe two. Regardless, testing this way, you'll at least know conclusively about the front four and might know about the rear two also.

In theory, if there is continuity on the rear two, you could make an educated guess on whether you have two live plugs on the circuit or only one based on the resistance you find, but that requires accurate measurement equipment that most inexpensive handheld DVOMs can't achieve. If you have an excellent meter, though, and can use it well, you have the potential for making some more conclusions.

If you find dead plugs, you have your issue. If you find 6 live plugs, then it will be less clear, still could be a glow issue (voltage drop or bad off-brand plugs), or could be something else affecting cold combustion (some severely worn or damaged injectors, or compression). However, your description more or less rules out loss of fuel prime as a cause. If cycling the plugs multiple times changes it, and if the systems are relatively consistent, then it's not a fuel supply issue. Air leaks tend to be less consistent in behavior (often affected by parking angle and other factors). Leaks at the advance arm shaft typically don't cause starting problems either.

FWIW, you can replace the two O-rings for that arm quite easily without removing the IP or getting it rebuilt, takes some care but not difficult at all. But I wouldn't suspect it as a cause for your concerns.