While dynasties allows us to play minor factions, they are a bit bland in my opinion. With COHORTROYs mod they have their unique units but they still just have one building to make all of them, no strings, no frills. Not under my watch! So I'll give them a similar treatment to all the major factions. Unique buildings with unique benefits and drawbacks providing CHTYs UUs, select native troops and a few major faction units that make particular sense.

Let's start with the Aegean,
1. Because that's where I finished on the main factions.
2. Because there are a lot of units and premade concepts there because of troy and
3. Because I'm currently on an agamemnon campaign.

Achaeans:
Like mycenae the other “greek” states are centred around their citadel barrack. Like mycenae they reduce training slots, buff associated stats on recruitment, cannot be damaged and can only be built in the Aegean + Cyprus. Unlike mycenae however each faction only has one variant instead of two. Outside of the Aegean they have access to a less flashy building that just goes to t4 and provides a basic selection of a ahhiyawa troops as well as the chariot maker and islander recruitment. All of which are shared with mycenae.
Ithaca: focus on skirmishes - light nimble troops
Boiotia: focus on defence - spearmen and slingers
Aiolia: focus on charge - spear chargers and shielded infantry

Pelasgans
Lycia follows a very similar motto, but they do not share their buildings with troy due to the way troy is centralized. They have a pelasigan version of foreign barrack and chariot maker, and also use the achaean islander building. And of course a unique citadel barrack:
Lycia: focus on archers - archers and defensive infantry.

Thrace:
The thracians(and phrygians) don't rely on province capitals as much as other factions. Instead their barracks are dependent on the terrain(or rather resource type) of the region they are in. Apart from plains, the other two can be upgraded fully in minor settlements. I could do careful analysis which regions are forests, plains or hills but I think this is 1. Tricky due to slot types. 2. Less balanced 3. Not really worth it.
Plains(food): chariots and shieldbearers.
Forests(wood): skirmishers, Archers and Clubmen.
Hills (bronze, stone & gold): Chargers.

Phrygians:
Like thracians phrygians are dependent on terrain tho like myceneans they have to choose between two improved barracks in preferred settlements, which can be fully upgraded to tier 4 even in minor settlements, while the non-specialized one only goes to tier 4 and that only in major settlements.
Skirmishers(wood or gold): more ammo, wood production bonus.
Warriors(wood or gold): more melee attack, gold production bonus.
Raiders(all settlements): mix without elites.