We can try all the solution in the universe, but nothing works out if your team is not fully involved. So you need to make them understand the importance of being in sync and it involves a lot of mentoring as well. But again, in the end, it depends on the INDIVIDUAL. No matter what you do, regardless of your best effort, some tends to drift away and you need to move them out of the group to have better team.
And keeping a team happy, well, good luck with that!