Hello thanks for the interest in our plugins. I can answer your questions.
We do not have a RSVP feature out of the box.
You can use WooCommerce (or one of our other ticketing solutions) but this typically would require the customer to go through a checkout process.
We are interested in adding this feature so if you upvoting this request on UserVoice that helps us to prioritize new features and functionality.
And our ticketing solutions are not directly tied to the user roles so it would take some customization to do what you describe in questions 2 and 3. We can help on that customization with a question or two, but would not be able to completely add that feature.
Thanks