Project and Product Managers lead our teams. They help define the roadmap and create tickets in our kanban board. We'll try to define MVPs and create tasks to get there.
Teams meet weekly for at least 30 min and will either work by themselves or with others throughout the week. We create small tasks with realistic timelines to ensure that volunteers don't feel overwhelmed.
It depends. Expect volunteer projects to run slower than a paid one. Our teams work iteratively to ensure we are thinking through the problem space rather than devising a solution. We aren't our users so we try to do our due diligence through stakeholder and/or user interviews.