The Sonos Port should work with either option.

From the Sonos Port FAQ:

Port’s RCA input can connect turntables, CD players, iPods, DACs, and other audio devices, allowing you to stream vinyl, CDs, and locally stored audio files to wireless Sonos speakers throughout your home.

I have just a slightly different opinion to @GuitarSuperstar, but you may need to double check what I very quickly read online…

You can certainly use the Sonos Port for the Onkyo CD Player - as it has RCA line-out to connect to the Port’s Analog Line-In, but I don’t think the Bose wave music system has such a line-out connection? At least, I couldn’t see one mentioned in the manual I quickly glanced through.

So you may want to just double-check my thoughts about the Bose Wave Music System, if you do decide to take a closer look at that player instead.

@Ken_Griffiths Could he use a 3.5 mm to RCA adapter from the Bose headphone jack to the Port?

With the Onkyo consider a Five instead of a Port. It has a Line-In which can be played anywhere, and is also a speaker that would trounce a Bose. 

Headphone out circuits vary widely in their output impedance and level range, at least that’s my understanding,

The "line level" out on something like a CD player, for example, typically has a high output impedance, whereas a headphone out will usually have a much lower impedance to be able to drive headphones.

But ‘yes’ it will work - however given the choice, I would go with the Onkyo player as it does have the line-out RCA connections.

I think @ratty’s suggestion of using a ‘Sonos Five’ is a good idea too - that’s if the OP is looking for a speaker aswell to add to the setup.

Thanks - this helps to confirm my preference to go with a CD player with a carousel. The additional suggestion of the Five instead of the Port is good - I had not figured out that option. Thanks!

One more dumb question: if I use the Five, can I still play the music from the CD player on the OneSL speakers we already own? (I am assuming that I can do this with the Port, but not as clear with the Five.)

Thanks!

Yes, you will just group the Five with the One SL speakers you already own.

Yes, like I said, any Line-In can be played on any device in the system.

You don’t have to group to play a Line-In, unless of course you want to group them.

Excellent! Thanks for the solid information!

I wouldn’t invest a lot in playing CDs, once I got busy ripping mine I have never had the CD cabinet open. In fact I gave away the CD player. 

Putting your music on a NAS is fairly easy and far more convenient.

1. You need an SMB v1 compatible NAS or a computer that Sonos supports to host your music.
2. You want to rip it into a lossless format, I used FLAC but others work well too.
3. You want to use a tag editor to get all the music’s tags set to work well with Sonos. A few special characters in them or the names can cause issues.

But if you own a lot of CD's you could reach the 65k limit on Sonos’ database, for which Plex is a work around (since Plex on Sonos does not have a folder option).

I hadn’t thought of doing this with my old CDs. I mostly stream to Sonos from Apple Music but assume that a lossless ripped CD would produce better quality audio? Or is it similar enough that the time spent ripping a few hundred CDs just isn’t worth it? Appreciate your opinion. 

 I would rip them as first choice, just stream the music as a second choice, and use a CD player as third choice.  No, actually, That wouldn’t even be my third choice.  My main reasons would be convenience and sound quality, although I don’t think you will notice a huge difference in quality.

If you just ripped 20 a week they would soon be done, and you can do other things while ripping.  Don’t use iTunes or Windows Media Player, they both have their eccentricities.  I used dbpoweramp, although that is Windows only, not Mac.

13+ years ago I spent a solid 3 weeks ripping several hundred CDs to FLAC (EAC, foobar2k, etc) and scouring the web for art.

Given where we’re at now, I think I'd just subscribe to a lossless service and only rip the CDs that I couldn’t find online.

I’ll typically play the latest online version anyway, even when I have a rip of the original album, as the recording’s often been remastered into a ‘deluxe’ version.

My one reason why I would still rip today rather than just stream (and this reflects my use of the system, not claiming it is right for everyone), is that I have lots of my favourite tracks in Sonos playlists consisting entirely of locally-stored tracks.  I don’t want playlists tied to a particular service.

Like @ratty , I do now mostly stream (lossless) all the same.

I love my ripped CDs for many reasons, Sonos is what got me started but I use a down-converted MP3 copy in the car and on my laptop. Handy when there is no Internet.

I don’t hear well enough these days to tell the difference an an Amazon Music stream or a FLAC ripped CD. 

I approached ripping as a project, fired up every computer here that had a CD reader, added my USB CD readers and loaded them all with CDs. Had about a dozen running in parallel so I was busy swapping CDs. First shot at uploading them to the music library turned up a few compatibility issues but a batch-mode tag editor fixed them in a few seconds each. Fiddling the Genre tags to get the albums grouped as I like took longer.

I’m not close to the 65K limit and I don’t think I am close to the other storage limits either. Never bothered to submit a diagnostic and ask Sonos staff to give me my storage numbers, they aren’t visible to users.

I can see that I will have an ongoing project to work on over the next year. Thank you for the collective wisdom!