Play in Veteran mode rather than Cadet. Or maybe try Options ---> Difficulty and disable "Extended Map Info" for Cadet mode.
NB. This will also make the tanks invisible on the map.
Units, vehicles and buildings need to have symbols, so that you know when you've placed them in the mission editor. Certain difficulty settings then hide this information. I don't think you can selectively choose to display only some.
Is it necessary for these guys to be Civilians? If you group them with a high-ranking (ie. Colonel) officer on another side (eg. Resistance) with a Probability of Presence set to Zero, then they will be considered part of that side (ie. Resistance).