Ah, looking at the extra drawings, I think that person on the train is Hinase's Doctor.
Also, as for the gender roles things, while true that this manga is kinda 'this society but one things different' for something that is changed of this magnitude, it would be too alien to us to relate to us in anyway if such a thing was shown but gender roles would be more hard and defined their then it is in our society.
Although I think it would be only recently that the children would have been allowed to choose their own gender as a parallel to our societies own gender struggles.
Just thinking about how much of the society would change in some areas but stay the same in other areas is so interesting. Hmm, one thing that'll probably change is that women suffrage would happen way earlier there then it would happen here, probably in their renaissance period? Maybe earlier actually, probably sometimes after when government started taking a census of their population.