Need help with integrating zoom webinar with eloqua

Dear all, 

We are trying to use zoom webinars and create an automated process using our marketing automation platform aka Eloqua. While we are able to get the registration details from zoom webinars into Eloqua - we are unable to have options to map the fields as per our organisation's rules / policy.
The questions we have are
1. is there a way to get the embed code of the zoom webinar form
2. is there a way where we can have options to choose which zoom webinar fields get mapped to which of our CRM fields
3. Is there a way we can set up forms with picklists - if yes how and where can these be defined
4. When we use an eloqua form to feed registrants into zoom webinar - our registrants are required to re-register using their details prior to joining the session, ideally it should not ask for the emails again.
Kindly advise
Thanks