JST,
We did a site seeing trip up to Hyder about 20 years ago, however there were folks fishing salmon on ?fish creek? outside of Hyder. They even had their fryers setup cooking right on the bank. That trip was during the month of August, so I'm sure you'll find activity there. Sorry, I don't have intel on the halibut.
PS I do remember seeing numerous bears when we were there.
Greg