A: Yes. Edit the flow (an active flow is paused first with Pause and edit) and click the end point. Under Behavior, choose Loop flow, set a Delay in Weeks or Months, and click Save. Contacts that reach the end of the flow wait for the delay and then start over from the beginning.
A contact only starts over while they are still in the flow's segment. Contacts that reached the flow goal, or matched an End flow if... condition, leave the flow and do not start over.