A: yes you can vape in KSA, however there are some rules you have to obey. no vaping in shopping Malls/ restaurants or cafe.
Keep in mind you have to be 18+ to Vape its considered as Tobacco Product in ksa region.
A: Yes, Vaping is legal in Bahrain. you have to be 18+ years old. But keep in mind THC, CBD is not LEGALIZED and you will get jailed if you are caught.