Crowd-powered group therapy session scheduling

Any suggestions for themes, plug-ins or custom PHP scripting for this project?

Requirements:

1) Crowd-powered group therapy session scheduling with a trigger that will schedule a session once a quota is met.

2) Ecommerce integration

3) Social networking/marketing integration

We could take the web dev project to Drupal but I would prefer a WordPress solution.

My client wrote:

“Looking for a development partner. Overall, we need a brochure type site with content management for most areas (WordPress would be fine, but open to ideas). The unique part is that they want website to include a menu of events and classes with custom interactivity: Menu or calendar of events should be interactive, so that interested users can ‘like’ the things they find interesting. Upon reaching a certain number of interested users the event would then get scheduled, automatically sending emails to interested parties and notify the therapist who will be running the event (with as little admin effort as possible). They would also like the website to be the place where people pay for the event or class. Social networking integration is important.”