I’ve only ever tinkered with openmediavault, so I’m by no means an expert, but there is a ZFS plugin available. Here’s a forum post that may help: https://forum.openmediavault.org/index.php?thread/7633-howto-instal-zfs-plugin-use-zfs-on-omv/
That fruit argument is so that samba plays nicely with Apple’s SMB client implementation.
That will be totally doable, but there’s no one way to setup every service. Some you’ll install from the repository (like nginx or HAProxy or samba). Others you’d have to clone from git (like netbox or dokuwiki). Others have entirely different methods. So, unfortunately it’ll be a lot of reading the documentation.
In general, I prefer unprivileged LXC to a full VM unless there’s some specific requirement that countermands that preference (like running an appliance or a non-Linux OS).
What I tend to do is create a new container for each service (unless there’s a related stack). If the service runs on Docker, I’ll install that right inside the container and manage it with docker compose. By installing Docker directly from get.docker.com instead of the built in packages, it pretty much works all the time.
Since each service is in its own container, restoring backups is pretty service-specific. If you wanted some kind of central control plane for docker, you could check out swarm mode.
I get pretty much anything Michael Lucas writes. The information is always great and his writing style is fun to read.
Important to note: it’s not a step-by-step guide to copy and paste and have a mail server running. It’s all about understand all the stuff that goes into it.