1) It is extremely recommended to do so if possible, though of course whoever leads the congregation in the home must fulfil all the conditions of a prayer leader as mentioned in Islamic Laws of Ayatullah Sistani (Baligh, sane, Twelver, Adil (ie one who doesn’t sin openly and repents after sinning etc).
2) I’m not aware of any specific narrations but given that Imams were under political persecution most of their lives they would have prayed jamaat at home most of the time.