We can say Atropatene isn't going to be in. It would be impossible to fight against the seleucids and it would make the Hai even more difficult.

I think we will see a Baltic faction as most of the land there is still unused.

For an Iberian faction, maybe the Cantabri(http://en.wikipedia.org/wiki/Cantabri) might be a good one: it was one of the last Iberian tribes to hold out against the Romans.