Yes, Iranians (aesthete ? Qajar) were the most supposed on discord. And it was added like this in the speculation spreadsheet.
We know than there is Industrial Germans in the game. We have seen them in some screenshots with the militarist affinity symbol. Maybe their name or affinity will be change until their reveal.
They had the specific
https://de.wikipedia.org/wiki/Schwarzes_Kreuz_(Symbol) for emblem in screenshots.
And U-boat (EU) and Zeche Zollverein factory (EQ) were supposed by screenshots/artworks. Again thanks to the discord poeple which identified all of this.
Obviously it's not sure, there is sometimes generic unit/building with emblematic skin (like the generic european district looking like Garnier Opera).
The modern/contemporary era is really uncertain,, really curious how this era will be represented. But I am really dubious about modern Turkey. I see them regularly in wishlist / speculation list.
The most part of industrial/modern era, Turkey was really in bad times; it's recently than there is a big revival of their military forces and of their economy (which it's not stable btw). It's seems too recent to be represented in the game.
They were hurted so bad by Ottoman's fall, all their territories exploding, being neutral or pawn in the modern wars, with unstable political sphere, coups, ethnic problems, ...
I prefer to see original cultures which we saw rarely in 4X games, born from the dead empires, like Yougoslavia, ...
In my humble opinion, I prefer to make a "what if" scenario, with trenscended Ottomans, and let some place for other culture. (And I hope to see some 'Turk" additions in previous era, like Seljuks for medieval. To have some clash with Byzantine, an Mamluks aha)
Italian is possible for industrial yes, Meiji or modern japanese, why not, or later in dlc. Like you said, "without focusing on particular regimes", we need to have good and unique "Archetypes" for each era, to create our own culture.