It is hard to see a massive change in the house in the next 2 year election cycle.
I don't know. Last night was pretty ugly for a bunch of 2010 freshmen.
However, many of the 2006 freshmen, despite party affiliation, have A ratings from the NRA and a good record on guns. Support for the 2nd Amendment doesn't split along party lines.
Back to the question of new Justices, they can be hard to predict. Take the case of Justice Souter. I doubt the folks pushing for his appointment really expected him to end up ruling the way he did on many things.