Domain mapping/purchasing proceedure...

Hello, my business model hinges heavily on the customer not doing anything technical. Also, warning...this is a long multipart post.

With that in mind I would like some clarification on the domain mapping plugin procedure. Here are my questions...

1) eNom credit card processing:
I assume this is eNom's so called "Rocket Registry" (found here: How does Domain Mapping handle this? Does it use the eNom API to conduct the transaction and keep the individual on my site? Or does it forward to Rocket Registry to enter credit card info? If it is the latter, will they be returned to the same page after the transaction has occurred?

2) Domain set up:
My understanding regarding post domain purchasing is as follows...the customer must still set their CNAME or A Records and point them to my site. Ideally this should be automated using the eNom API (is that even possible?), but for now...given my business model...can I set this up for them? Will I have access to their domain settings?

3) Domain ownership:
Who is the officially registered user/owner of the domain? Is it me? or is it my customer? What happens if the customer stops paying? Does the domain go back to eNom, or would it revert to me?

4) How is the charging occuring?
Is the customer being directly charged by eNom? Or am I being charged by eNom and the charging the customer? Or is the customer being charged by eNom a price that I set?

I know that's a lot at one time, but I want to make sure I understand exactly what I'm in for. Thanks in advance.