LOL...I use MC as a short term for Main Character. Other times, I might use PC as Player Character...though MC has its uses...as you point out, emcee (a host).
Yep. The biggest key to getting the Architelone is to have someone with at least Int 1...so you can do it with Com 2, Int 1. (Com 2, Charisma 1 won't do it)
If a noble, you should be able to get your cousin's help (Ismene) to know the time.
Pretending to be a noble won't work, whether noble or Helot MC. I don't think it is possible with a helot (Pretending to be a noble, etc. requires a combination of Int and Cha, I think).
Or, you can force the Telone to work with you. This works for both Helot and Noble MC. You need to bring Elery with you, then attack them with silence. From there, it should proceed as normal.