Well, it's not easy to answer. Cause istanbul is a very big city with different areas in. So if you're in tourist region, you may eat, drink something and also smoke, without a problem. But if you're in town like Kad?koy, Besiktas, Eminonu you may still smoke but honestly it won't be polite. Best way to discover; Look around to find out what local people do :)
absolutely.! Turkey is a secular country. It is ruled with democracy to people are free to practice their religion. all kinds of bars, pubs and restaurants are offering alcohol during ramadan. So feel free to smoke or drink alchol during ur stay!