[X] Unreliable, but may sometimes be necessary.
[X] It all depends on the situation. Sometimes fear can be used, sometimes you can trick them, sometimes you might pretend to be an ally, it all varies. But, I think one thing that almost always remains constant, is that you want them off balance.
[X] Force the location of the item or person out of them, or let them lead you to it, or possibly hack their phone or something and steal the info, or maybe something else. It all depends on the situation, and how you must adapt to it.
[X] Adaptability
Gonna have to go with Ness on this one for the first three.
For the last one, I'd say having the proper intelligence going into a situation is good, but hiding our presence or identity might not always be possible. In those cases, I think adaptability is going to help us in the end.