0/ Is this path reasonable?
Yes, or use the orbit mode.
1/ Where is the take off point?
Red circel is fine.
2/ What happens after the final waypoint is touched?
Depends on your mission settings & RTH behaviour as described in the drone’s user manual.
3/ How does range work?
The mini 2 is a so called VSC-drone and needs a constant & good connection with the remote conroller to run waypoint missions succesfully:
4/ Any other tips?
Read at least the Waypoint and/or Orbit section of the online user guide: https://flylitchi.com/help#waypoints-p3
Read at least the RTH-section of your drone’s user manual: