You won't be able to get any decent phalanxes as Epeiros in Pergamon (AOR)...

The sanest army I can think of is a solid line of classical hoplites along with thracian units as flankers (they are recruitable in Asia Minor as Epeiros). You have thracian pelstats there with their insane swords, also good medium cavalry. Should be enough for flanking power. Especially after you get some chevrons. Some galatians might be priceless too.

Add to that some heavy mercenary cavalry (Thessalians?) and you're fine for most of the game. Classical hoplites + thracian peltasts can take any heavy phalanx out there without even getting tired. And phalanxes is what you will be fighting against most of the time.

Resign from archers, they are hardly ever useful against all the heavy stuff you're going to fight against and you can't really retrain them. I'd stay with thracian pelstats for most of the game as missile support for they are deadly.

On second thought, you could make a trip and create a colony in Crimea where you can train those awesome armoured archers. It's short way shipping them from there...

On strategic level, I advise using units you can retrain, you will be tight with cash for most of the game so housing depleted units might help a lot. Also, you could consider leaving your historic house rules for a while and really consider taking some places that might be very useful for you but weren't actually Pergamon's subjects back then. Like Rhodos (for slingers), Crete (for archers), Lesbos (to get rid of Makedonia), Crimea (for archers), Nikaia and Byzantion (to seal your lands from Greek incursions)...