Hey man.

As for the interview, everyone said it. Relax and teach the guy. If you passed the checkride, you are already good to go. Just show him what you already showed the FAA.

As for the second job, my previous employer told a few students if they went from Private to CFI in 2 years (while taking a full college course load), they would be guaranteed an interview for a CFI position. Guess how many of them became instructors after then dropped all that money up front...?

Any employer who is tell you something like that is milking you as a costumer. Don't get suckered!