Hi. We’ve started this. It will be available as a part of our new SSL It! extension.
Since Plesk Onyx you will be able to install memcache as a Docker container and configure http(s) proxy rule for it to map to your web app.
Docker and proxy rules are available in Plesk Onyx Preview already, you can try it here https://talk.plesk.com/threads/plesk-onyx-preview-and-feedback.337172/
BARE METAL! - do it and do it php7 ;-)
otherwise we could start an VM inside the VM with a Docker inside handling memcached :-D
full dns should be an option for each domain inside the settings of the cf extension
by activating full dns it should show up new nameservers from cf for the registrar update