I think you might be trying to make it more difficult than it is. It makes no difference which/what account a domain name is registered under, or hosted under. All that is required is that the DNS for the registered domain is pointed to the correct nameservers for where the site is hosted.
For all Dreamhost hosted websites, irrespective of what account they are hosted under, those DNS settings are:
This is true even if the domain was registered with another company, if the hosting is on Dreamhost. The DNS does not care what account is involved, only that the nameservers are the correct ones for the host.