Okay the boxes are all single duct cooling only. How do you provide heat? Does the AHU have a reheat coil or is there any baseboard radiation? Does this AHU have a morning warm-up mode? If zones require heat during the occupied mode it looks like they have to go to minimum position and thats it.
Typically I see a low supply air temp control scheme with series fan powered boxes. Why is it a problem to use a supply air reset?
What is wrong with using an average temp of some interior and exterior sensors to reset the SAT. If you include the meeting rooms in the average I would think it would be a good start.
What did they require for VAV minimums? 20%, 30% or higher?
Why are they concerned about mold, because you are raising the SAT above 55 deg? Can you trend the space %RH with a return air %RH sensor?