Draco definitely wouldn't have done it if he had more time. But he feels he didn't, and he jumped at the best option he could find. (He would have been especially screwed if he'd decided to depend on Harry to raise the money, for instance).

Daphne really is pretty much what she appears: self-sufficient and only interested in people for a few things.

Draco's definitely always looking for hidden motives. I think Harry has learned to do so, but only for people, like Draco, whom he expects to have them.

In this case, Harry will endeavor to learn more about Draco, because he does understand that what he sees may not be all there is.

And thank you!