Also, is there another more active FDD discussion group?
Do you have a question about FDD Tools? I am one of the co-authors of the FDD Tools application, and would be happy to try to respond to any questions you might have. FDD Tools is referenced in the Resources section of this website.
Regarding your second question, I am not familiar with a more active FDD discussion group. (Which is to say, at least to my knowledge, discussion around FDD at present is fairly limited.)