I tend to doubt that fishers and wolverines are close competitors for the same food resources or ecological niche. Fishers tend to keep to mature or old forests, hunting prey like Douglas squirrels or red squirrels. Wolverines really love high elevation, remote wilderness, although they may traverse low elevation areas at times. Just my thoughts.
Likewise, I think it's great to see them documented in various parts of Washington, although Cougartail is probably right- probably not going to be a large population. As climate warms, wolverines are losing the deep snowpacks that they need to raise their kits. Douglas Chadwick's book, "The Wolverine Way", gives a good rundown of wolverine biology and conservation- great read.