The ones you mentioned and those Juro, Eric, and Mark list together cover steelhead flies very well. Bill McMillan's Dry Line Steelhead, Trey Combs Steelhead Fishing and Flies (this is no longer in print; but should be relatively easy to find), and Deke Myer's Advanced Fly Fishing for Steelhead offer some PNW steelhead flies not often seen.
However, as Eric has mentioned, there has been a real incorporation of Atlantic Salmon flies and fly styles (like Ally's Shrimp, Irish Shrimp style flies, dees, etc.) sometimes as origianally tied sometimes with more traditional steelhead colors in PNW steelhead flies.
Veverka's book on spey and dee flies and Mann's book on shrimp flies also cover some very important newer developments. There are also quite a few of us who have learned much from the likes of Kelson, Francis, Blacker, Knox, Price-Tannat, Maxwell, Bates, Hale, Hardy, etc and who have found that many of the old Victorian era salmon flies work very well on PNW steelhead.