Q. If avelim are given permission to sit shiva and daven in a Beth Midrash that does no ordinarily have a daily minyan, does the ba’al tefila omit tachanun and lamentzeach (ya’ancho Hashem) and all tefilos not said in an Ovel’s house?
Is seating shiva at a shul a correct thing to do? Would this be permitted in a Beis Haknesses?

A. Horav Shlomo Miller’s Shlit’a opinion is that since this minyan was organized albeit temporarily, for people sitting shiva, they follow all shiva traditions of tefila.
It would be correct for people to sit shiva even in a Beis Haknesses, as long as they do not eat or sleep there. In a Beis Hamedresh however, even the above is permitted, for the one’s learning there. (See Shulchan Aruch O.H. 151: 1-3).
It is also a great act of chesed and kindness, to permit the ones who need, to have a place where to sit shiva in their times of sorrow and loss. (See Mishna Berura ibid. 5).

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a