Even if someone takes the time for a phone call, that call would be more productive if you would list what you have so that person can research beforehand. Or even better, you could.
I'd recommend splitting up the questions and researching separately. For example if you decide between using shimano X vs. SRAM Y or cable rim brakes vs. hydraulic disc brakes. No one here can guess what you have.
You also should list what you intend the bike to do. For example gear ration will differ for road vs. MTB use.

Based on the information you provided I advise you should take the derailleur from the large box in the corner and the wheels hanging from your ceiling.