Oh ffs! No they're not! These questions are attempts to establish a connection to you - maybe you work in a similar field to them (or one that they find interesting), or grew up near to them, or have kids the same age.

They are making small talk by asking anodyne questions.

If a stranger asks you “are you married and do you have kids?” and you respond by telling them about your sex life, they will end the conversation with you.

Well, no, they are asking about what your life looks life and what fills it. It’s also subjects which open easy way to relate to someone: “we both have kids”, “we work in related fields/they work in the same field that someone I know”, “we both like this sport”, “we have been around/travelled to the same place”. That offers a wide breadth of conversation starters.

Not at all. Those are valid questions. In some parts of Asia, those are the first questions you'll get, including your salary. You might as well get that out of the way from the start.

I'm going to start saying: "Art Vandelay", Architect