There's some precedent set here, based on the Warriors of Darkness we encounter in 3.4. Going off their names in the solo duty...
  • Arbert is a Warrior, same as in our world.
  • Blanhaerz is a 'Knight' rather than a Paladin.
  • J'rhoomale is a 'Ranger' rather than a Bard.
  • Naillebert is a 'Magus' rather than a Black Mage.
  • Lamimi is a 'Devout' rather than a White Mage.

It seems to me like they all use FF3 jobs. Most of the FFT/FFTA job names probably exist on the Source, too, in the Dalmasca region, given they appear on a lot of the raid gear from Rabanastre/Ridorana/Orbonne.