Ok, so I didn't realize but there is a no-move function built into the EOS script, however, the AI mod my unit uses (LAMBS AI) overrides the "do not move" command.
Basically what I had to do was add another line before the do not move command to disable LAMBS AI on the unit
so with that edit lines 149 and 150 in SHK_Buildingpos.SQF read as follows.
if _disableMove then { _x setVariable ["lambs_danger_disableAI", true]};
if _disableMove then { _x disableAI "PATH"};
I also had to switch { doStop _x; }; for { _x disableAI "PATH"}; as units would still move with { doStop _x; }; set as the second command.
Now this doesn't seem to work on units that are spawned inside manually constructed buildings (for example a Hillhouse we have that is a bunch of separate objects put together, none of which would be classified as a building)
I assume the EOS script isn't applying the commands for a house patrol to those units since they technically weren't spawned in a building (though only house groups were set to spawn)
In any case, I'm not too worried about that, if I populate the Killhouse I'll probably use some other method with manual location selections.