Input limited

Sorry gents. I should have mentioned I have a Sony cassette deck and a Teac open reel. The tape in/outs are used. My SAE 5000 is using the Adapter loop (originally for a Dolby unit). My EQ unit will be in the pre in/out loop.

I am left with Aux for the CD and Squeezebox.

So you are out of inputs. Your options now are to use one RCA and switch it from CD to Squeeze, or 2 RCA and swap them at the amp. Or if one of your tape decks is seldom used for recording, then you could run the CD or Squeeze into the REC input of that deck, and when you want to listen to it flip the deck to REC and monitor the line level through the deck.

Hard to find a plain audio switch with all in/out on the back. Next best thing includes composite video.  Found these 3 😊

https://smile.amazon.com/gp/product/B079ZVKF8R

https://smile.amazon.com/gp/product/B0753CQ668

https://smile.amazon.com/gp/product/B07C15XGQN

There's always the Manley Skipjack.

Well 1 in and  4 out with a rotor switch is gonna be the safest. Can't hit two sources at one time and reverse the way it goes into the pre.
1 out 4 in.. on a rotor switch.. PE sell them I'm sure

Regards