As far as I've seen, and has been ruled in other games, the Telepathy ability doesn't give any ability to read thoughts, nor give the target any ability to respond in kind. It's just projecting thoughts to another.
For two-way communication, the Message or Sending spells specifically note that the subject has the ability to reply.
For two-way communication, the Message or Sending spells specifically note that the subject has the ability to reply.
Regarding the first question, insight vs deception.
You can disguise the voice using deception.
The target has to answer within its means, if it is not telepathic itself it can only communicate via other mediums.
I'm open to discussion on this, I'm just trying to go with where my intuition would think things would be.