There are no simple answers here, and it very much depends on the team members, their history working together, their professionalism and maturity. For junior

There are no simple answers here, and it very much depends on the team members, their history working together, their professionalism and maturity. For junior / inexperienced teams a much more formal structure will have to be set in place, with lots of management input. For more mature team members or teams who have a longer history working together less structure is required and perhaps even preferred because formal structure just tend to get in the way of getting things done. Lastly be careful of trying to evaluate the merit of everyone's individual contribution. You get different contributor types, where you get the loner archetype who creates massive amounts of code but doesn't communicate with the rest of the team enough, or the team player who maybe don't write the same amounts of LOC's, but keeps your team cohesion healthy and happy. You need all different types of contributors on a successful team, rather measure the teams output and reward everyone if the team perform. With the exception that if the team starts complaining about a single slacker in the team you address the issue.