Register as RedHen Contact entity?

There was a similar feature request once: #1653458: Register an entity different than a user

The question is: is it possible to make registration based on RedHen Contact entity?

We run a school, and we store our students as RedHen contact entities. They come to our courses once or twice a year. We must store the registrations for years, because the courses are based on each other. So we shouldn't lose any registration.

The real problem is: we get many registrations on paper, and not everybody has an e-mail address. So there are no drupal users for them, and the email addresses are changing frequently.

So I have 3 problems with current registration + redhen_registration implementation:

1. Registration based on User entity: When user is detached (or deleted) from the contact, the registration is lost for contact entity.
2. Anonymous registration: When the contact changes his email address, he loses previous registrations.
3. We can't register contacts, who don't have email address.

The question is: is it possible to make registration based on RedHen Contact entity? It is possible to develop/code this?

What do you think? Is there a way to achive what i want without tons of custom coding? Any advise or guidance would be greatly appreciated.