Don’t think City would sell to a domestic rival, unless they were trying to merk either party hard, but that could quickly backfire. Word is City would want £15m-£20m but would sell for around a third of that to a foreign club.
Guess it depends if you think Courtois really is Madrid-bound or not. If you don’t then it’s a non-starter. Even if hypothetically Chelsea were prepared to pay the money, Hart’s not going to move somewhere as a backup ahead of a major international Finals.
Courtois will stay where he is. Hart will go to an Everton or a West Ham and play every week.