I've found out more on how to get units to stay put after a SAVE Game:
In addition to these commands:
loon disableAI "MOVE";
loon setUnitpos "Middle";
I've added these commands:
dostop loon;
loonLeader enableAttack false; <== use this command only on the group leader
Now after a save game, the units do not abandon their positions. They stay put, and keep their assigned stance. And they continue to fire (note that enableAttack false does not prevent firing, it just prevents group leader from ordering units to engage--i.e., move toward--enemy).
There is still one problem though: Units that "need ammo" will run off and get it, not caring that it is a suicidal move. So be sure to load up those units that tend to start the game short of ammo (i.e., officers, crew members, pilots, etc.).
This is not a bullet proof solution, but its better than nothing. Still looking for a way to detect a save game, so we can restore all disableAI conditions immediately after saving or loading a game.