1 is a pretty easy push IMO
2 I like a flop push too...looks bluffy/drawy and likely to get looked up by aggro types. If you are up against a nit, I wouldn't push though.
3 I probably lead turn. Likely go broke
4 I think a river call is read dependent. Flop cbet is bad, but turn check shows weakness. He can bet missed draws here all day.......