Before getting started: Some things to remember: One, I’m assuming you’ll have local access to the server in question. Thus, not needing SSH, etc. Two, Plex, ownCloud and WordPress all work great on a tablet. Just enter the IP address or better yet, set up static IP addresses on your router. Bookmark them and you’re golden.
You could potentially run the entire thing on something as light on resources as a **Raspberry Pi. A better alternative might be an old desktop or laptop you’re not using.