I agree with your points apart from what I put in bold.
High vis is pretty important at night. It's definitely better than dull/dark clothing. It's doesn't take a massive lack of concentration to miss a cyclist/pedestrian who is wearing dark clothing.
At night it's lights, reflectors on moving parts like pedals or legs and then reflectors on jacket and as others have pointed out they are of no use unless you are on a sit-up-and-beg type bike , for bikes you want reflectors on the seat of you pants or on the bottom of a backpack. Hi Viz/light clothing might help a bit but is absolutely no sustitute. Sharp Contrast is better than a larger blur. Reflective surfaces on a black jacket would stand out better.
|There's multiple parties involved and all parties should contribute to the safety of others.|
Back on topic
When it come to collisions with cars the main use of a helmet is as a Hi-Viz hat. It can be a large bright , reflective surface that's up high in line of sight.