Greetings,
Well, we got this to work. But, I'm not sure what I did that enabled MIDI back to the CTX-5000. In the hopes of helping someone else...
Opened-up MIDI setup on the MacBook - nothing to do with LogicPro at this point.
From the MIDI setup there's a utility called MIDI Studio (I think that's the name, my wife's MacBook isn't near me now to check)
I deleted the icons for our old Yamaha and a Roland that the machine remembered from a visit to a music school
There's a Test function in MIDI Studio and when I tried that a sound played back through the CTX-5000's speakers!
Closed everything down...but still no luck.
Then we restarted LogicPro in the simple mode (before we had been using advanced mode with many more options.
This worked. The problem is that I'm not at all certain what I did that "worked". I was in a LogicPro clicking frenzy as after I heard sound back from the Test function, I was sure it was possible.
I should have updated my post, I'm sorry, to have given a result. I wish I had done this more scientifically so that I knew what I did that enabled sound back. The speakers on this keyboard are wonderful and my wife really likes the Casio vs the Yamaha. Only thing is the Yamaha is much lighter and can run off batteries, but that's not such a biggie.
Take care!
Bradley