I wanted to accomplish exactly the same but the Rsvp information isn’t available unfortunately. The summary information isn’t available either even though it should be.
To get round these limitations I added my own collection and created functions in events.js for onRsvpCreated, onRsvpDeleted, onRsvpUpdated and on EventDeleted. This works for Rsvps created through the dashboard, the Wix booking form or Wix velo.
If it would help I could post the code from events.js if that would help.
Regards
Doug