There was no official announcement of a third movie in the Cold War series. Although there were some rumors and speculations, there was no conclusive evidence to show whether there would be a third episode in the series. If you like the " Cold War " series, you can pay attention to the latest developments of the movie or wait patiently for the official release information.
For the girl, maybe Zendaya would be great. She has the acting chops to portray a strong - willed young woman in Rio. As for the baby daddy, I could see Oscar Isaac. He can bring that mysterious and charming quality that the role might require. And for the 'God Girls' group, actresses like Yalitza Aparicio and Lupita Nyong'o could be part of it. They are both very talented and could add a lot of depth to the group of friends.
I'm not entirely sure specifically which 'rio true story' you are referring to. It could be about a person named Rio, or it could be related to the city of Rio de Janeiro. Without more context, it's difficult to say exactly.