For now, it's enforced at the support level only.
It will be a hardcap soon (no precise date announced yet). Upgrade to be compliant to prevent issues in the long term.
Global phonebook and it technically is disabled in MCM.
But honestly, if a customer needs CRM integration, use a dedicated instance. Never a shared one. You would hit too many limitations.
We built this using CFDs. Much easier and simpler, with a backend DB.
@VoIPTools also has a great tool built for this.
I wouldn't bother reinventing the wheel.
Just set the archive to 30 days. Backups will include local ones until then, then they'll be moved to the archive, which you can then manage retention on that side.