I was at a shiva minyan this morning but the mourner was not there (he was running late from the airport and some people could not wait). He showed up in the middle and went in to another room, then to the basement where we started another minyan. The following questions emerged:
would the minyan without the mourner follow the shiva-minyan practices (no tachanun etc) if he was
A) in the room but not davening
B) in the house, not davening
C) in the house davening but not with that minyan
I can imagine a case where the mourner davens with his minyan, and then many people show up and set up another minyan -- the mourner says kaddish during it, and is in the room for it, but isn't "part" of it. Would it matter if he, though he davened already, was number 10?
Related to this, but my cases all happen in the beit avel.