1) plus the number of edits to un-templated articles in the same category, I suppose
2) of those active editors, have they ever posted on Wikiproject talk pages, and if so, which ones? (we should be able to create Wikiproject editor profiles based on # edits to WP talk pages)
3) How to measure participation? Signup page or posts on WP talk pages?
4) it would be nice to know this for overall, e.g of the active editor group of +/- 3500 on enwiki, what percentage has ever written on WP talk pages and who are the top posters?
5) Can only think of one (military history)