Iblis was not an angel for a single day, not even for an instant. He is one of the jinn. The angels were created noble; they never disobey Allah when He commands them to do something.

1- It is possible to talk to the jinn, but finding out about unseen matters and what is in people’s hearts is haram. 2- There is nothing wrong with talking to the jinn if this happens without you seeking it, and in fact it is mustahabb to call them to the religion of Allah.