You could use another cloaked wraith owned by the computer, and just put it closer to the wraith, just outside of range, using Mobile Grids.
None.
Wouldn't making sure the "Always order observers to their repsective players" triggers execute after the AI script do it?
None.
Hm. I think Mobile grids would screw up because there's almost always another flying unit it the general vicinity, and burrowed grids wouldn't work because half the map is unwalkable. Right?
Yeah, that may be a problem then
Have you tried ordering the Observers AFTER running the AI? Also, giving them to another player may erase that AI from them.
None.