Easiest way to do workshop registration with a way to gauge interest in classes first?

I'm a part of a community run makerspace, and am thinking it would be cool if we could post our ideas for a class and have people "RSVP" for it, essentially join a waitlist to be notified when it launches.

I think having an intuitive UI would be important to making this work, which is where I'm running into a little bit of difficulty figuring out the best way to go about creating this. Some important features are:

1. A dashboard of all class ideas, in order of when they were posted.
2. The ability to "RSVP" to a class idea to indicate an interest in attending.
3. The ability to see beneath the listing how many people have RSVP'd, similar to Meetup.
4. A way to register people for a class once it is launched so they can pay ahead of time.

If anyone knows of an event registration platform that can natively do this too that would be great.

Obviously there's a makeshift way to do this with waitlists and event maximums on some platforms, but I'm looking for a UI that makes the feature to indicate interest with an RSVP clear and intuitive.