I think critical thinking and healthy skepticism are good things samseb. I could not agree more that discovering what is real has made life rich and interesting. My take on your questions follow.
#1 As stated previously, there’s not a lot of science behind Rational Recovery. It’s a method, and a very useful one for many people, but it’s not based on empirical knowledge, at least as far as I can tell. As a matter of fact, neurological studies have shown that emotion is critical for good decision making (see the work by the neuroscientist Antonio Damasio).
#2 I find it more useful to accept the parts of myself that I don’t like and seek to change them, rather than to split them off and deny they are part of my “self”.
#3 Whether you call it beast, parasite or anything else, and whether you view it as a part of your'self' or not, I think it’s important to recognize and to take steps to counteract the influence, in whatever way works for you.