Characters with Telepathy have an obvious avenue to Create an Advantage on an NPC's character aspects by probing their minds or memories, and usually have narrative permission to attempt doing so. Depending on how the power is defined, the NPC might be aware of such probes when other routes would be more subtle (like a detective going through police records or a hacker doing Internet searches). You can use this as a trade-off, letting the telepath gain information that the detective or hacker don't have access to at the cost of tipping off the target.
Can a telepath take control of an NPC's mind? In general, if that NPC can't offer significant resistance and it advances the plot, you should allow it as a simple Overcome. On the other hand, taking over a major NPC's mind and puppeting his or her actions can be a mental conflict, with the Taken Out result indicating total mental control.
A character with mind control could roll to achieve their real objective, bypassing the Overcome and justifying that roll by saying "I've mind-controlled a suitable target". This is best when the outcome of a failed attempt to control someone's mind isn't interesting, or success at the take-over itself seems certain.
Certain telepaths might be able to acquire new information or skills. This can justify using their approaches to make rolls outside of their stated areas of competence (like a telepath doing surgery on a comrade, based on expertise copied from the mind of a brilliant doctor).