I have been watching this thread.
If you said issues when hot, then I go to electronics since they can fail with some heatsoak (a sorta common failure).
If fail when cold, I would lean away from coils (mostly spark plugs or cam/crank sensors, cold usually helps).
If you think it's a sensor/coil connection, maybe pull the connection apart and twist (assuming flat pins) a bit, like 5-10* so it sits firmer in the mating plug.
Also just plug/unplug sensor and coil connections a few times may make things better.
I sorta hate intermittents, I prefer a dead die.......then check.
Yes, usually the crank trigger is what drives the tach in the car......no needle movement when cranking, bad sensor......wiring.....tach.