A Chinese friend drew a distinction between Zen and Taoism as philosophies and as religions. As philosophies he said the approach is a very openended search for understanding. As religions, however, the approach becomes much more rigid, ritualistic, and concerned with "proper" adherance to predefined rules. I think this is analogous to what happens with theories and methods of therapy. The originators of theories and methods engage in openended experiments and search for better ways to understand. Well intentioned students, however, search for perfect and "proper" ways to emulate their teachers. Part of the genius of Erickson seems to be that by never formulating his own specific theory he ensured that the methods could continue to evolve (another therapeutic bind or use of paradox).
On the subject of compatibility with psychoanalytic theory, I would expect that as a psychiatrist who started practicing in the 1930's Erickson must have been trained in traditional psychoanalytic theory -- even required to go through analysis. I find it very interesting that in all that I have read so far about his methods, there is no mention of the influence of other theories. It just stands to reason that his phenomenal undertsanding of human behavior must have developed within some context. I strongly suspect that there is a great deal to be learned from studying the ways in which Erickson's methods are based on, extensions of, or reactions to the discoveries of others.