CF DNS Under one Partner Account

We are building a custom dashboard for our public cloud and will be adding Cloudflare DNS as well as other Cloudflare features for our cloud hosting customers. These customers will be able to signup and control their Cloudflare account through our dashboard.

Separate to this we also intend to use Cloudflare for our DNS service and need to clarify a new things before we commence that part of the integration.

  1. Can we use our Cloudflare API key to allow customers to add their domains to our partner account for DNS purposes without signing up for their own Cloudflare account ? As we want to use CF DNS for our customers cloud virtual machines I think this is the most effective way to integrate such a solution but need clarification if this would work or there is another option.

  2. If customers then want to use Cloudflare features ( as well as DNS ) they then can signup and use their own CF name servers.

To be put simply we want the most effective option for customers JUST to use CF DNS and use our partner account API key and name servers ( we will be purchasing our own vanity name servers ) for DNS and then once customers want to get all the CF benefits they then can signup.

Knowing the above I would be interested in knowing if this is viable and the best way to go about such implementation.