Thanks, SpadesFlush and Ken,
Just for clarity, I don't intend to use both technologies at the same time... Just one or the other... And, I hadn't intended to have S&T and a CD running at the same time... I might like to do some testing with the S&T and a CD and, if S&T will break in with the voice announcement, this would be a nice feature... But, it is/was not a goal for me...
While FM transmitters can be expensive, the one I linked is refurbished and only $9. If it didn't work or shortly failed, I wouldn't have lost much. The main factor was/is how it would source the voice announcement. Since Ken advises that it all comes through the same sound chip, this shouldn't be a problem.
The cassette adapter only has one cable for the audio feed. They do not have a power cable.
Great conversation and information, guys! Thanks.