Alternative 4 will be the less troublesome of the options in my opinion. I think the clients will cache all important data on the local SSD, so it should be very snappy. I've not noticed any annoying latency's on my clients.on is renaming of files and adding or editing cover art and similar images for media.
This is correct.
You're overthinking it a bit, mdav. When MC connects to a remote Library Server, it caches the entire remote library to: C:\users\<USERNAME>\AppData\J River\Media Center 18\Connected Library\
From then on, all "use" is made from this cached copy, not from the network connection directly. MC periodically merges the cached copy with the Library Server copy in the background, so that you get new changes (and commit your changes from that Client).
So, unless your fast SSD isn't the one that contains your AppData directory (which wouldn't make any sense whatsoever), you'll get this benefit automatically. When you initially open MC on the clients, it has to download the Library, which makes MC launch
slightly slower, but that's the only "speed related" change you should see from running locally. Once it is open, it will "feel" local. And, on a LAN, that initial connection to the Library Server process is
extremely quick (especially when you're using a SSD on the client). I only see the "Connecting To" dialog box on my HTPC for a split second before MC opens.
Option #4 above is absolutely the best choice if you don't want to keep PC#1 on 24/7. The main things you'll need to consider/realize are the limits of what you can do from a Client copy of MC. I don't think they'll be too tough to work around, but you should be aware of them:
File Locations:All media should be imported into your Library on the WHS box using a drive letter or UNC path that "matches" on all the clients. Video playback, for one, will work much faster and more reliably if the client copies of MC can "find" the actual media files on disk over the network. Otherwise, MC uses its built-in streaming functionality. That's great for sharing files out over the Internet when you don't have a direct connection to the server PC's storage, but if you are on a LAN, there's no reason to do that because you can mount network shares and MC won't have to transcode and do all that work. This will also allow all of MC's "file management" tools to work (like drag and drop, Locate On Disk (External), and other similar things.
There are two ways to accomplish this:
A. Put all media on the WHS box on a volume with a drive letter, and then share this entire volume out in Windows. Then mount this share on your other PCs using this exact same drive letter. So, if your drive is called M:\ on the WHS box, share the whole thing, and then go to each PC and mount a M: network drive pointing to that share.
B. If your media is on the WHS box in a variety of places, or on the C drive, option A will not be easy to implement. Instead, make the shares on the WHS box as appropriate, and then import the media into the copy of MC running on WHS (the Library Server MC) using the UNC paths instead of drive letters directly. So, for example, if your media is in C:\users\<USERNAME>\Music (and Video, etc), share each of these top level directories, and then import the media into MC using this path (these work in Auto-Import and everywhere else in MC): \\servername\Music\, \\servername\Video\, etc. If you've already imported your media using C:\etc\ type filenames, you can easily "move" them in MC using the Rename, Move, and Copy tool in Find & Replace mode.
Library Setup Limits:While MC fully supports tagging and whatnot from the Client-side, there are certain functions in MC that can only be done directly from the Library Server itself. This comes down, mostly, to this: You can't change the Library structure at all. Any changes made to things like Views, will be lost the next time you reconnect the Client. This means that all Library Management tasks must be done directly on the server (or while connected directly to the Library, in any case). This includes:
A. Adding or modifying Views in Standard View, including sorting, categories, columns, etc.
B. Adding or modifying Views in Theater View, including View Style (thumbnails vs. lineup vs list vs 3D style views, etc).
C. Adding or modifying Views in the Media Network setup of MC (DLNA, Gizmo, JRemote, and the entire REST API of MC).
D. Unless it was changed with MC18 recently (which is possible, I haven't checked), you can't delete Playlists from the client-side either. You can modify existing ones (but watch out, it can get funky occasionally if you do things like restart the server without closing all the clients first), but you can't delete any of them.
So, while you can easily maintain your files from a Client copy of MC connected to a Library Server, you have to do modifications to the Library itself on the Server.