What are the risks and dangers of ureteral stenting and laparoscopic surgery to remove 5-8mm endo nodules behind vagina wall and on right ureter?

Very little. Stenting of ureters is done by some endometriosis surgeons to help identify the ureter during the dissection. It has little risk in an of itself. If a stent is left in place after surgery it can cause some pain until it is removed, though it may still be needed.