What's the best way to arrange my online magazine multisite ?

What is the best way to organize an online magazine on a multisite, wherein the main site is the magazine, and on various subdomains are the following:

-social network and forum (buddy press and bbpress)

-e-commerce store

-various subdomains for specific magazine content types.

-possible subdomains for user blogs

1. Is it okay to have buddypress/bbpress running on a subsite, not the main site?

2. Is there any special way one should go about this?

3. Does this sound easily doable?

I run an online magazine for a niche sport, using wp single install converted to multisite. http://www.trikkeworldmagazine.com/

Thanks.
Diduwin