Can you give me the quotation from the Mishnah about the minimum number of people that can study Torah? As I recall, the first Rabbi says ten and gives a quotation, the next says seven, etc.

You are probably referring to the Mishna in Avot: "Rabbi Chalafta says: ten that sit and learn Torah, Shechina is with them...", he continues - even five, three, two, and finally "even one who sits and learns has a reward...". (Avot 4) He brings a Pasuk for each number. Rabbi Ro'i Margalit