I own a '96 Chrysler Voyager with the original radio with an AUX connector
and no CD changer, I see there are 3rd party interfaces to connect cd
changers but it would be enough for me to connect an external player. Is it
possible to connect the analog source to any pins of the AUX connector and
tell the radio about the presence of the fake cd-changer?

If not, would it be any good to use an audio(tape)cassette adapter (cables
around) or some rf generator to tune the external source on a radio station?
Any link on the net?

Thank you