In Forms 10.4, you can make a team member a Team Manager.  According to the Administration guide:

From this page, team managers can edit teams (edit team members, team roles, managers, and set team task visibility), view assigned team tasks, change due dates and priorities for team tasks, and reassign tasks to other users or groups. Team administrators can perform all the actions team managers can perform plus they can edit the team name and description, as well as delete teams.

We have created Teams and made a Team Manager in each team so they could add and remove members and assign roles. But is looks like that the only way for a user to be able to access Team Management is to be given the System Administrator which is a product-level security setting.  

Is there a way to give a Team Manager access to the Team Management settings in Forms without giving them System Administrator security?