The crew are young, fit and attractive, and no doubt are intellectually and emotionally compatible; and they have probably been training and working together for months now. I wouldn't be surprised if strong emotional bonds hadn't already developed amongst them.

I doubt there will be any complications over the duration of a short mission like this one. But it would be very interesting to consider the social dynamics of a voyage lasting months, or years. I have heard rumors of long duration (simulated) missions that have ended badly due to interpersonal social issues. Sexual conflicts are not the only ones we need to worry about.

It would be understandable that any social problems arising from long term isolation and confinement of small groups would not be widely publicized by those undertaking this testing. And we must have experience from coed crews on naval vessels, polar research stations and the like. I hope someone is taking notes.