Pontus=easy as pie, nice bronze shields, chariot archers, scythed chariots, cappadocian cavalry (like Cataphracts) and good archers.

Seleucid Empire=If you can survive the first onslaught, build up Antioch and Seleucia, and start churning out enormous units. If you can, take Parthia and Armenia while they are weak, Pontus too. Then you can focus your entire military might on Egypt, and you should win. Egypt assassinated my 10 star commander, so I assassinated the assassin, then killed their faction leader and faction heir (in battle at Thebes) then finished them for good.