Direction & Blood-Relation Puzzles

Sonam is walking facing north. She turns right. Rishi thinks "turning right" always means turning to face east, no matter which direction she started facing. His teacher says it is correct this time, but not always. Who is right?

Raj says, "I am my father's only son." Kunal thinks this does not decide whether Raj has a sister or not. His friend agrees that "only son" does not settle this either. What is the right answer?

"My father's sister's husband" — hearing this relation, Tanu says this person is her "mama" (maternal uncle). Her brother says this is wrong, it is a different relation. Who is right?

A boy walks 3 km north, then 3 km south. Deepti thinks he has traveled a total of 6 km, so he is now 6 km away from his starting point. Her friend says this is wrong. Who is right?