Is this pocket door header load-bearing?
Firstly, reason 2 is invalid. Even narrow openings would require a load-bearing header if they carry floor or roof framing above.

Also discard reasons 3 and 4. Only the largest of headers call for two trimmer studs on each side. This one wouldn't even if it were load-bearing. Pocket doors can be and were installed anywhere a standard door might go.

Otherwise, I agree. You should be able to ascertain that there's no load resting on this header. The wall plate that runs across it should be visible from the attic, under the insulation. If that's clear, you're correct. A truss over the wall that's the same in bearing and design as the adjacent trusses isn't a concern.

This is a rare load-bearing question that has all the necessary information in it to make a confident answer. Bravo. That said, there may be factors we can't see. That's the drawback of asking the internet what it thinks. Responsibility for your safety and financial well-being still rests on you.