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So it dawned on me (which I’m sure Richard and Jeff also said but I ignored - sorry guys): the TStat is only for turning on the zone pump and the toe kick fans.  The heat in the AquaHot tank is separate - it is controlled either by the Diesel boiler or either of the 110v/220v electric elements inside the AquaHot tank.
I now know a LOT more about how the A/C and heat systems work… I don’t think I’m ready to replace gurus like Rudy but I’m learning!
BIG thanks to Richard and Jeff for all their advice and loss of hair while working with me!
Now I need to test the whole thing with the A/C units! I’m sure I will find other stuff along with needing to fix some leaking AquaHot pumps…

Ahh yes that is a good point, the t-stat should only be turning on the zone pump and the associate heater core fans. FYI the zone pumps can also be shared by other t-stats for your bathroom, closet or even basement heat that can call for a zone pump to run. It just depends on how they configured the zones. I need to figure out which ones do what on mine, I have not bothered yet to figure it out. 

As you mentioned the aquahot boiler temp is purely regulated by snap discs located inside the aqua hot, there is one for the AC element and one for the diesel side. Its good to know about these, they can sometimes be an issue. So you are correct that the diesel burner is not going to kick on immediately when the t-stat calls for heat. It will eventually turn on once the temp inside the boiler drops to the set point of the snap disc.