BuddyPress Activity Plus Multisite Installation

My web site is set up as Sub-Folder type of Multisite. The root site is the main site for information, yet the sub-site is for the blogging and social (BuddyPress).

BuddyPress & Activity Plus are both activated ONLY in the sub-site, cos we want to make sure that the root site and the sub-site won't mixed up and the subscribers cannot mess the root site by accident. In fact, the root site and the sub-site are having different themes.

So, is it necessary to Network Activate both plugins in order for them to work properly?

We're currently testing our set up and Activity Plus is not behaving 100% as expected.