Mike,
i'll second going to flounder bay. They will have the epoxy (system 3 a 2:1 mix ratio) and wood flour (it's just flour const. sawdust). They'll also have the oak you need if not, windsor plywood here in bellingham has oak that long too. The people at flounder bay are very nice and will be very helpful. I personally would reattach another sheet of 1/4" over the 1/2" you might find that without the extra layer of 1/4" you bottom might flex a little more than you may want it to when sliding it over a rock. I also agree with the point made about the wood being able to breath from the inside, and besides if you were to put on the coat-it or gluv-it on the bottom it would be the same as fiberglassing and epoxy, seals it up just the same.
As for weather flounder carries hardware i'm not sure. I think they may have some.
I've been following along with your project updates and have enjoyed your posts.
If i can be of any help feel free to ask i just finished up a wood stitch and glue power dory at easter and have gone through a lot of epoxy and fiberglass.
anyway, good job on the project and i look forward to seeing the finished boat.

chumsalmon