Take 1
Ancient era - Scythians,
Greece, Celts
Exploration era - Slavs or Great Moravia, Hungary,
Byzantium
Modern era - Poland, Czechoslovakia or Ukraine,
Russia
Bonus civ: Bulgaria, can go either to the second or third era.
Benefits: fairly uncontroversial take for all national sentiments. Scythians->Slavs->Poles would be very cool for Polish people, who'd
hate being era II civ forced to turn into Russia or Germany, and "modern era" apparently includes 17th century (see Mughals). Similarly Czechs and Slovaks wouldn't complain about Celts or Scythians->Slavs->Czechoslovakia, and both Ukraine and Russia could be derived either this way or from Greece->Byzantium-> while avoiding all possible political drama.
Meanwhile Hungarians would be relatively fine is this model as they could transition into Poland, traditionally close and friendly nation.
Another benefit of this setup is how it accomodates Bulgaria, which I think would be acceptable for them either via
Scythians->Bulgaria->Russia
or
Greece->Byzantium->Bulgaria
Take 2
Ancient era - Slavs, Scythians,
Greece, Celts
Exploration era - Bohemia, Poland, Hungary,
Byzantium
Modern era - Austro-Hungary, Bulgaria, Ukraine,
Russia
The opposite take: Czech and Polish people get to be medieval and renaissance, Slavs are ancient using logic of Missisipiana and Khmer, meanwhile Austro-Hungary is the only somewhat acceptable modern era civ for Poland, Hungary and Czech to transition into (medieval Germans could also go this way)), while Russia and Ukraine or Bulgaria could still develop from Greece->Byzantium->
Personally I prefer Take 1 because going from Poland to Austro-Hungary would still feel kinda lame compared with ending the game with Poland
