Trump's so erratic it's silly to pretend there's ever been a master plan, but the conservative media empire escape hatch seems like his best play after the train wreck. Trump and Bannon are going to get paid and Ailes gets some revenge.
While they may not have played their hands perfectly, Pence (avoid a career ending loss in IN, play for 2020), Cruz (2020), Kasich (2020?), Ryan (2020), and Rubio (2020/2024?) made reasonably good moves.
Newt, Rudy, and Christie don't have any other future options, so they had to sign on. Carly's a desperate clown-Cruz was never going to get the nomination and RNC Chair realiy is a crappy job.
Conway doesn't make much sense. Buys time via a pay day and adds another entry on her resume, but that's all dependent on a close loss. Trump goes off the rails again, he destroys the GOP and she takes a fair amount of blame. Also find it hard to believe that she doesn't realize Pence or Cruz and their brand of social conservatism is still going to be viable in 2020. She already may have cynically written off winning national general elections, but knows there's still money to be made in the 'Pub presidential primaries.