Simmons will do whatever he wants, the others will depend on how they're playing in the NBA whether they can dictate, and whether they'll make the team.
The team should be aiming for gold, they showed they could compete with the USA in Rio. The system is superb, especially offensively, and the roster will likely be more versatile in 2019 and you'd assume 2020.
The big question for mine is will Bogut be there, because having playmaking bigs is importance for how the Boomers play. If he is there how much will he play? If he's not there which players fill that role?