rogerdn, magister and tony22,
Thank you for your very helpful replies to my inquiry. I’ve got to look into MinimServer, MinimWatch and metadatics (I am a Mac user).
The limitations I have experienced with DSM, Audio Station, File Station include, as rogerdn notes, that they don’t allow me to stream DSD files. But more important, as a Mac user for years, I have grown to expect applications to be relatively intuitive and to some degree “idiot proof,” or Steve Jobs might have said, “bozo proof.”
I also expect user documentation to be easy to use. In general, documentation for DSM and various applications (Audio Station & File Station) on the SynologyNAS is not easy to use.
As I have downloaded music files to my SynologyNAS, for example, I have somehow managed to get two copies of tracks for several CDs on the server. So, every time I move one of these albums to the “Playing Queue” each track appears twice in the queue – i.e., 1-1, 2-2, 3-3, 4-4, etc. This is annoying because it is not easy to remedy the problem by removing the duplicate tracks, and I can find no information in the documentation for the NAS that tell me how to identify the cause and permanently remedy and avoid this problem in the future. It is not as obvious as having two separate instances of the album showing up when the files are sorted by album; the album shows up only once.
Another problem is that, because my NAS failed, I returned it under the warranty. Although all music files were preserved on the two hard drives that I removed before sending the NAS back to the manufacturer, all the album art I had entered was lost.
One more issue: I rip all CDs to my iMac using iTunes (using AIFF files). Then, I download them individually to the NAS using Download Station. I would like simply to use the functionality in iTunes to download and store my music library, as organized by iTunes, to the NAS.
However, I have not yet been able to find an answer to the question: If I do this, will DSM/File Station/Audio Station be able to recognize these music files and serve them to my DSD and PWD (I have two systems on my LAN – one uses the DSD, the other the PWD).
My sense is that the SynologyNAS software is meant for those who are relatively adept at system administration, and I cannot lay claim to any know how in that arena! 
I am grateful for any advice and information I can get. Thank you.