Hi, you don't get to choose who you play as. The game alternates POV between the male and female main characters. Currently there is no cuckold content in the game but if it is added it would be avoidable depending on your choices.
Hi, the story is being written along the way so there is no set schedule. Eva mentioned that around 20 chapters would be a realistic prediction but who knows how it goes.
Hi, a steam version is being looked into but the normal development of the story takes precedence. So eventually, yes, but we can't tell you when exactly.