About Atropatene: Don┤t know, but I guess yes, cause there is not much free space in the era.
But I would love them - the east needs more diversity and factions. Usually most people suggest only (western) european faction from Ireland and Scotland to Belgae, Greeks in Gallia or Spain (Massilia, Emporion), Celtiberi or a second german faction.
But as all seven culture slots are in use they won┤t include them. The EB team is looking about historical accuracy and when their family members would look Hellenistic or Semitic (and have also those names, architecture and traits) it seems not right for them.