[Yentz]

1)
I give up on the turn, the second Q is a good card for almost whatever hand he is willing to call turn with.
2)
I dont know, you obvously might fold out a missed flushdraw.
He is not folding much else he calls turn with I think, since you might have a missed draw too.
3)
I like betting river here. The K is such an obvious card to bluff on the turn, so he might peel once with pp, pair+gutshot etc and fold to the river bet
4)
I think the last barrel is fine here, he needs a pretty strong hand to call. You might be able to bet a bit less without getting called much more. I might bet 280 or so, I doubt he will bluffraise this river giving you great odds.
I am not sure about that though, would like to hear someone elses opinion.