You cannot refactor without a comprehensive suite of tests that you trust with your life. If you have that suite, refactoring is always easy and free of risk. A moment of refactoring becomes a trivial thing rather than a huge risk.
The existence of "nonperformers" on the team is a sign of dysfunction. Where's the mentoring, the education? If you're working as a team, you work to improve the team and everybody on it. If you're a bunch of isolated individuals, unwilling to help each other, you're not a team.
Rewarding "individual contributors" is a common antipattern in DarkAgile. It's actively destructive. It's the team that's doing the work, after all, and if it's not (if an individual is carrying all the load), you need to address that dysfunction. 1/