I'd personally give Juguntiz a special standing as, especially the chatti ones, are eager to kill thier first enemy and get their Real spear and thus becoming "proven ones" so Imo most realisitc would be to not disband them until they get a chevron from fighting rather than temples and game fields. after that you can train them again as Dugunthiz. Levy spears and Skutjanz are levied troops or troops that just fight to protect house and wife.they have a regular job in the community and are just marginally fond of fighting(except maybe a little raid to gain some gold and glory once in a while ;) )

if you want a 3 level unit you could add the swordsmen as they not only killed a man in battle but have had the opportunity to kill a man armed with a sword(which are far more plentiful gaul than in the village next door). so you could replace Dugunthiz who earned a chevron in combat with gauls(no spearmen do not count) or romans with Herunautoz.