WordPress Multisite Packages

I’m working on a project that requires very specific restrictions and I’m struggling to grasp how to set it up. I’m just looking for some direction on which plugins and settings might be combined to achieve the required result.

The scenario:

I’m running WordPress Multisite and allowing visitors to register accounts and sites. When they register a new site, I would like to limit their Dashboard to have access to ONLY two plugins.

My first inclination was to use the Pro Sites plugin to create packages, however it appeared that sites could be registered without having to pay for them. Is there a way to force payment with a site registration?

Second, is there a plugin that you could recommend that will hide/disable everything aside from a plugin tab within the newly registered site?

Thanks in advance for any direction you’re able to provide!

David

EDIT: I also wanted to inquire about the Blog Template plugin. Perhaps I’m looking to combine its functionality with Pro Sites? Or just use one or the other?