I have been studying the washless process.
Regarding retained silver levels, it is the silver metal specks that remain un-bleached that cause problems with image quality (grain, sharpness and color). Used properly, there should be none of these specks in a washless process, just some traces of silver halide complexes. The silver halide complexes retained in a washless process cause a different problem. They can affect image stability. I have no information on this whatsoever, but having examined the chemical changes in the bleach and fix, I see what they have done, and it follows from R&D I am familiar with and have been working on myself here. It can work. It apparently does. I have gotten good results from it. In fact, Super Universal Fix VIII uses similar chemistry based on my R&D at Kodak.
SUF VIII uses a method of swelling gelatin which facilitates removal of silver halide complexes from the coating and allows reduced wash times. It also forms a different type of complex.