When is the typical end of interview invitations for faculty positions?
I don't think there is a single answer here. Some schools start their interview process in late fall, and other schools don't even conduct preliminary interviews until the end of February. In addition, there's always the possibility that nobody accepts their initial offers, in which case they may want to start a new round of interviews. So basically, you can get an interview request until you get a rejection letter. 

However, I would suspect that the bulk of interview requests go out by late February.