1. Verb “Have” is tricky when you translate from English to Korean because 가지다 means more likely “Take” in Korean. So I would better use 친구이다 or 친구가 되다. 2. And also you should say ~까? With question instead of ~다. In Korean, uncertain subject is omitted usually. So, I guess that you need specific name there instead of “for instance, 수지. 4. “In the world” is probably an emphasizing words. We usually tell “제일” instead of 세상에서. ___은/는 “수지의” 제일 친한 친구입니까?