Yea, I just googled up the interview where Kanan mentions all these things you said (as interests/possibilities), I had not read these interviews:
https://heavy.com/entertainment/cobr...urns-season-4/During the interview, Kanan also discussed how he believes Mike’s life turned out following the events of “The Karate Kid Part III.” He noted that he would be interested in the character joining the military, where he becomes “a good guy.” He then revealed that he could see the martial artist making a career out of being “an anger management coach.”
In a way it might be fitting thematically, fit the trend, if Barnes joins Chozen and Johnny in the "former young bully beaten by LaRusso and later become good guys" club. The "old" guys (Kreese, Terry) stay the same (more or less), but the kids changed, Daniel/Miyagi broke CK's hold over the young bullies.