BuddyPress.org

Right now the only way to really have it on some sites and not others is to simply give the sites that don’t want bp a theme that is not bp capable. Then for the sites you want to use bp, simply assign them a theme with the bp functionality in it.

The problem comes into play in that if site ‘abc’ has bp enabled and so does site ‘xyz’ then site ‘abc’ will see not only their activity/groups/etc but the activity from ‘xyz’ as well. Kind of ruins it. That is why I am trying to figure out how to filter the data output to only data relevant to the site being displayed.

Not sure what you mean by one template per site. Running bp requires a ton of templates just like the base bp theme has.