Welcome, IanT. I will hazard a guess that you are British.
Chocohol does sound odd--would one drink it or eat it?? I can understand the usage, though: chocolatic simply doesn't carry the connotation of addiction that alcoholic does.
Re: attendee--my preference is to say people in attendance.
An 'attender' strikes me as indication that someone is paying attention, not always the case in an attendee.