To answer your questions:
1) Depending on the position and size of the stones, the options are shock wave lithotripsy or flexible ureteroscopy. The more distal the stone, the more likely the use endoscopic techniques.
2) Typically lithotripsy is used for stones less than 1cm. This can be considered in your case.
3) I am not aware of a minimal stone size. Typically lithotripsy is more effective for smaller stones.
4) It may be possible to use lithotripsy alone.
5) It is possible that the stone may pass on its own.
6) If the stones do not cause symptoms, you may want to try to see if they can pass on their own.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.