I would NOT fold in any of these cases. It doesn't look like they could have anything special that would put you at a major disadvantage. It's worth it to see the turn. You will probably know if you won or lost the had at that point.

The last hand you should raise because you want to see if they actually have the flush or are chasing/bluffing. I had a similar situation last night but the 3rd suited did not come out until the turn. But he did not raise big enough to make me believe he had it, so I reraised. He actaully called (no reraise) and the 4th suited did not come out, but surprise surprise my 4 of a kind was completed. I put him all in. He had Ace high. This is common on low limit tables. If it was higher stakes, I would have reconsidered. I was on a .25/.50 table and took about $30 on that one hand.