Those are some mighty fine looking figures! I do hope they'll get into production or something, otherwise this is some horrid form of torture
About the question of the armour. Agincourt armour looks to be too old and WoTR armour seems too mordern, so I would go for Hussites. Closer to the 1450s and already look more Eastern European. Mixed with figures from TAG or Old Glory's Turks, Hungarians, Romanians and the likes to get an ecclectic bunch.
I think the Turkish style would have been dominant, then the Balkan styles and lastly the Western European style.
Lastly, perhaps we should call them the City-state of Constantinopel