1. 분 means "person" in honorific expression. ex) 여기 그런 분 안 계세요 There is no such person here. 손님 자리는 저 신사 분 옆입니다 Your seat is next to that gentleman. 다시 가족 분들이 미국으로 돌아가신 줄로 알았습니다. I figured your family moved back to the States. 친구 분 is honorific expression of 친구 팬 분 is honorific expression of 팬(fan) 팬 분들 is honorific expression of 팬들(fans) 2. 분 is honorific form of 명 used for counting people. ex) The history department has five lecturers and one professor. 역사학과에는 강사 다섯 분과 교수 한 분이 있다. Table for five? 다섯 분이신가요?

분 is an honorific form of person. 분 is also usually added before words and makes them sound polite. I suppose 친구분? is short for "저 분이 당신의 친구 분이세요?" which means "Is that your friend?" As for the informal version, it would be: 저 사람이 너의 친구야?

the way i know it is you use 분 when you are referring to a group of people for example 여러분 is everyone along with 모든분 also maybe a word you recognize is 팬분 "fans"