Components for a multiuser subscription site?

I am planning a new web-based service. I'm not sure which of your plugins I should use to build it out. Here are the general requirements for my new site.

* Public subscription service, per site, URL is

* Using Multisite, support many sites (hopefully 10000s), possibly multiple users in each, rarely more than 10.

* Individual sites typically have limited read-only audience, only via login (not typical public access)

* My private label for branding and identification (i.e., no WordPress branding)

* Site security and access control critical – actively prevent any “leak” of data between user sites.

* Proprietary themes/plugins provide unique content support features - users must not have source code access.

* Need overlay structure for posts, e.g., Project has 1 to M Subjects, Subject has 1 to M Pages, a page is a post.

* Need integrated customer service portal, with user management

* Need paywall per site allowing per site subscription at freemium, basic, medium, deluxe offerings.

* Need to allow a user to use any supported human language.

Please advise which of your plugins or themes would be appropriate.