Stlhdh2o -
While I'm not real familar with the Elwha the answer to your question depends on the species.

The resident rainbows and native char have the capabilities of resotre steelhead and anadromous char. Both groups of resident fish produce some smolts that would serve to re-establish those runs. The catch is will we let them.

There is hatchey on the lower Elwha that has at least chinook; maybe other species. Those fish would serve as brood source. The thing that made the Elwha chinook so large was the habitat that they used. Since once they get beyond the dam sites it still is intact selective pressure from the habitat should led to larger fish.

Tight lines
Smalma