United Registration Forms in WordPress

Hi Guys.
Nice to “meet” You ^_^
Listen please: I would really need a suggestion from You !!
I was looking for something, which can give me the possibiity to build 1 single registration form for my web-site. This is the situation of my web-site (which is still in “work-in-progress”)… I have on WP this plugins/features:
1. Gravity Forms (used to make Photo Travel School Registration Forms)
2. MailChimp for NewsLetter and Addresses Management
3. WP e-Commerce for FineArt eShop
4. bbPress for a little Forum
5. Other important plugins I use are, for instance GoogleAnalytics, qTranslate (I am implementing different languages), WangGuard …
Please …
HOW can I have a wp-page with a registration form (and “lost password field”, “user options” or “user profile”e etc) which users can fill in order to be at one time registered in the newsletter, as well as buyer and as forum subscribers ???
…
Thank You So Much! ^_^
PIETRO ^_^