here’s my ‘setup’:
yes, you can use just the mic jack for audio in/out/gnd/ptt.
the common way IS to use the speaker jack in the back because the AF out on the mic jack is routed/switched through the microphone.
this prevents any artifacts/feedback entering the microphone during transmit.
since we’re using a closed audio setup, you can take AF out from the mic without trouble.
this is good for 1200baud packet and vara narrow as well as all the narrow bandwidth soundcard modes.
lastly, you’re correct that there is no remote control/cat function on this radio.
good luck
kb0wlf