Here is my suggestions regarding the three cars.
Prius - Great fuel economy, comfort, and ride. In Karachi, you will not find trouble in finding specialist mechanic and spare parts including battery. You need to be mindful of bumpers and avoid pooled water or driving during the rain. Resale value may be poor.
Ciaz 2018 - Best choice if you want comfort and minimum maintenance during initial 3 to 5 years. Great resale value even after 5 to 10 years. Better looking car in comparision to Prius.
Honda Brv - Second best choice. Great for a big family. You should drive yourself with about 5 people to find out whether it's underpowered. Good resale value.
My personal opinion is to go for local manufacred cars and avoid imports like Prius unless resale and money is not a concern for you.