Can I install any extension within application and do you do custom work on the extension

Hello,

I have two questions:
1. Can I install any extension from within the application section (see attached) or do you have specific applications that can be installed from this section?

2. Do you do custom work like allow creating tabs for compatibility matches since I want to use it for a dating site? I want to be able to create two additional tabs/modules: Matches and Edit Matches. The matches will show users that are compatible based on completing a form with a series of questions. The matches will be based on scores and geographical locations.