If I recall the dual temp sensors may be slightly different. Or not. Damn this old age stuff. (I have a chart of resistance vs. temps somewhere).

Doesn't matter. You are correct, the engine management system uses current coolant temp in deciding various operating parameters. The biggies are the engine temp, and the mass air sensor voltage off pin #5 of the MAF. Other factors are involved, but in the ME 7.2, it'll run open loop until certain temps and oxy sensors, etc. come online. That means it's operating off of a learned table (base table from original modified over time by fuel trims determined during closed loop operation). As long as engine temp and mass air voltage is within a reasonable parameter, then by reference to its internal tables it'll have the fuel mixture (timing and duration of injector pulses), throttle idle position, ignition timing, and cam timing about where it needs to be. And no, that's not all there is being monitored even at cold start up - but those are the factors that place the initial parameters on the operating tables.

Engines are most sensitive to changes at idle and just above. That's why a MAF curve is steep at the lower end and flattens out. Higher resolution at low loads. Dunno about the starting issue as so many things can conspire to affect low speed running which may have no discernible effect at higher loads.