I'd prefer the OPoC proposal
In all the domains I have registered, all contact data infos are the same, they are all my address data. I see no point in this separation. The whole point of WHOIS was to have a contact address if either there is something wrong with domain or there is a technical issue that needs to be resolved. This was not about ownership, trademarks , buying domains, knowing who pays for it or any other marketing aspects, it was only to have an admin contact. And that is just one contact. For all other issues (including law enforcement and the like) it is easy to contact the service someone used to register the domain and they will have the address data (as they need to send bills for their service to their customer). So the OPoC sounds most reasonably to me. Just my 2 cent.
-- Best Regards, Markus Hanauska