Originally Posted by Terral

You absolutely can use NPC contacts without having "Talk to Contact" as part of the mission objectives. I needed a bunch of prisoners inside some cells for one mission, but friendly groups will attack enemies, and that doesn't work for prisoners. So, instead, I set up a bunch of NPC contacts that you didn't need to talk to and put them in the cells instead. If I did want to have the option of talking to the prisoners, I could give them a default prompt, which makes the discussion entirely optional and not objective based.