Chris Batin has made an industry out of showing people where to fish in Alaska. Chris's URL is www.alaskaangler.com, and he answers personal emails as well. He's published several books. 'Alaska's Trophy Gamefish' is worth a look (mines always being lent out) as is 'Fishing Alaska on Dollars A Day' (3rd Edition)which mentions Barnes Lake in NE Prince of Wales island as having good sockeye, silver and chum runs mid-August through mid-September (p. 66). Honker Lake has fair sockeye and silver fishing as well (p. 77). Black Bear Lake (Osprey might be onto something here!) is in central PoW and has rainbows, cutts and dollies (p. 67). I didn't look carefully but I'm certain your specific questions would be answered somewhere in there.

I know there are several medium- and high-end fishing resorts on the island that specialize in the saltwater silver and halibut fisheries. (Dave Vedder wrote about one of them in Saltwater Sportsman a month or so back, but I don't have the mag any more.) Do search using 'Prince of Wales Island fishing' and I'm sure you'll end up with plenty of leads.