[nu2trout]

The best thing I did was to get in touch with some of the guys in the Trout Unlimited group out of Hawaii. These guys can tell you about specifics, as I was finding a lot of what you have found. I have been in contact with on e guy in particular and he has sent me several emails. I think you will be fine to fish the time you will be there. Right now they are having some flow problems so they are telling people to come and catch as many as possible and keep them, trout that is.
Good luck with your research, and let me know what you find and how you do when you go.
I just purchased a 3wt 3pc Sage to take with me, since the trout are not very large and the 3wt should allow for some good fights.
I am also looking into some wading shoes that can take the stream and the trails, because the streams are very very slick and you will have to get out and walk from hole to hole, unless you want to swim through the really deep stuff. The good thing about the swimming is that there are no snakes in Hawaii.
There are wild hogs along the streams, but they are hunted and usually stay away from people.