Oh Wow. So many issues from that one post. Some bullet points. Sorry, I'm going to be a bit harsh, as this is basic MC functionality that you don't seem to understand.
You may have deleted the Dynamic Library (CazatonikServ), but your image shows that it has re-appeared and you have loaded it again. Just because the Dynamic Library, which is the DLNA Server on your NAS, appears, doesn't mean you have to load it. Don't do that. The only way MC could have found your existing Zones, as you state it did, was if you had loaded the DLNA Server Library again, which had all you settings still in it.
Dynamic Libraries are supposed to re-appear when they are visible on the network, generally. There is no need to delete them. Just don't load them.
If you delete a Dynamic Library I expected that MC wouldn't show it again, excluding it in the future. I wasn't willing to test that on my system. But it seems that the Dynamic Library from your NAS has re-appeared. Maybe it does re-appear if it was the last Library you had open, and you had MC opening the last used Library on startup. Make sure that the setting "Options > Startup > Library > Always load default Library" is ticked so that the "Main" Library gets opened when you start MC. At least for now.
Removing folders to import from the Dynamic Library from the DLNA Server on your NAS as your image shows will do nothing, as MC isn't loading files from folders. It is loading files from the DLNA Server.
You said you "created a new library and pointed MC to the drives on the NAS". Where is it in that image? I only see the default Main Library, and the Dynamic Library from the DLNA Server on your NAS. Maybe you deleted the new Library you created instead of the Dynamic Library as you said.
I don't know why the entire Library was duped when you create your new Library, but given the other issues in play here, I suspect that you included two paths to the same files on the NAS, which will result in duplication of every track. If you added NAS folders to import from into the Auto Import settings in the CazatonikServ Library, then you effectively told MC to import all files from the DLNA Server, plus import all files from the NAS folders, which would, of course, duplicate every file.
Now if you have set the Main Library to load at MC startup, as above, make sure that Auto Import in the Main Library only points to each Base Path location on the NAS once. So if, for example, you have a drive of say "M:\" mapped to the location of "\NAS Name\Music" on the NAS, and all your music is under that location, just enter "M:\" as the folder to import from. You could also just put the URI address of "\NAS Name\Music" in Auto Import, and that would work fine. Just don't put both in there. If you have multiple locations on the NAS that have music stored in them, and they don't overlap, then put those multiple locations into Auto Import.
As you are now using the Main Library, rather than the Dynamic Library as previously, you will need to do all your setup in that Library again, including all your Zones, Custom Views (you could export those from the old Library and import then into the Main Library though), and so on. Is this a big problem? Do you have a lot of custom setup?
It is not Best Practice to spend 40 minutes building a Playing Now list of files to play. It is Best Practice to build a normal Playlist, which will be saved as you go, and then just add that Playlist to Playing Now when you are ready to start listening. If you want to listen as you build, just build a small Playlist first and add that to Playing Now, start playback, then build another Playlist to Add to Playing Now later when it is ready. Playing Now can easily and unintentionally be cleared depending on settings and how you use it.
However, you said that you curated this Playlist in the Action Window, which means that you were actually building a normal Playlist, and not building a list in Playing Now. Then you double-clicked on the first track in your new, probably unnamed, Playlist. Then MC loaded just the first track from your Playlist into Playing Now, and played it.
It sounds like you have the "Options > General > Behaviour > Double click" setting set to "Replace Playing Now (single)", so MC did just that. Change that setting to "Add to Playing Now (play now)", or something more appropriate. However, even with that setting set to "Replace Playing Now (single)", if you were actually working in Playing Now to add tracks to play, and double-clicked on the first file, MC would not have cleared Playing Now except for the first track. It would have started playing the first track and left all other following tracks. So I don't know what you did.
If you had double-clicked on the new Playlist you just created, even with the above "Replace Playing Now (single)" setting, MC would have loaded the whole Playlist into Playing Now and started playback.
The "Recent Playing Now's" Smartlist is only updated under certain conditions, such as when you replace a list in Playing Now with a new Playlist. But you weren't working in Playing Now anyway, so naturally there were no "Recent Playing Now's" to go back to and reload. There was, however, the new Playlist you were building in the Action Window. That would still have been there, ready to reload. It just probably had the default name of "New Playlist" because you didn't even realise that you were building a new Playlist. Do you see Playlists called "New Playlist" appear from time to time, and wonder where they have come from?
If the total number of files you have is actually around 33,363, then the 66,726 shown is the number of files MC saw when it had imported all files twice, as above. That number might not get refreshed until you reload the Library, although I think it does if you refresh the View. Or more likely you took that screenshot after deleting the NAS folders from the Auto Import configuration, but before you saved the changes and ran Auto Import. Nothing wrong there.
The "total size" as you call it, shown as "13.5MB in library", is not the size of all your media files, it is the size of the MC Library files. That is, the size of all the *.jmd and other files that make up the MC Library, which is an index of all the media files you have. Nothing wrong there.
I was going to say I don't know why the MC screen was frozen, but it appears that you have deleted that post, so I assume that it wasn't really frozen, but was just taking some time to update the Library from the NAS or something.
I think I covered everything.
