Q: Proper solution for centrally locating files, music in particular?

I'm wanting to centrally locate certain files and eventually home directories (I think) on a Mac only home network (with the exception of an UnRaid server). I have a Mac Mini (mid 2011) that will be used for this along with other media server type stuff.

Things I want to eventually do:

• Move files/folders to a centrally located spot.
• Avoid duplicate files (more on that in a second).
• Save local HD space.
• Have a network backup solution.
• Be able to use laptop(s) remotely (i.e. not on local network).

Current computers:

• MacBook Pro
• MacBook Air
• Mac Mini on 10.11.3 (currently Plex media server and client)
• UnRaid Server (acting solely as large media backup)
• Network router with VPN already setup for outside access

The first thing I want to do is stop duplicating music files on the MBP/Air/Mini, without using iTunes Home sharing. Currently my wife has her music and library on the Air, I have my music and library on my MBP, AND I have them both combined to one library on the Mini for Plex (also in iTunes there). We have a bit of overlap in our libraries and then we each have stuff the other doesn't want necessarily. The big point here is that there's no point in having the music files themselves in 3 locations IF they're the same. And yes we have a family share account thing so we're not doing anything ontoward here.

Home sharing it too limited in my opinion and so is just using network shares without a server in the mix. I have tried using a shared folder on my Mini for music and pointing iTunes to it, but it always was problematic because the mount would drop after sleeping or whatever. And that was even with using automount to set the thing.

So after thinking on this quite a while I thought maybe I should try using OS X server and Open Directory which I think is what would make this work. Basically setup a folder (already existing) on the Mini/server with all the music files and set Open Directory to include this folder/share with all the logins so it will always be there for use. Obviously I'd need to go into iTunes on each Mac and point the media directory to this folder for use and since we share the files I'd set it to not copy files on import (since they would already be in the proper location). Then each user has their respective iTunes library databases, misc. media files, artwork, etc. LOCALLY so ratings, playlists, and whatever music they want included is all local.

Hopefully all that makes sense, if a bit long winded. I'm mainly concerned with accessing files locally, but still need to be able to at least login locally to a laptop if remote. There's no need to access the music files from remote, but if there was I should be able to just VPN in to get at them. But again, not a necessity.

At some point afterwards I would most likely move some or all user files to the server as well. Whether or not I would wholesale move the home directories is an open question. With local space on laptops dwindling, having a central place for files "most of the time" is beneficial. I just want things to be more or less seamless to the user.

Is OS X Server going to be my best option here? Any caveats to be aware of? Words of wisdom?