Hello TBP, thanks for responding.

Indeed, we are all friends of Jesus, now, if we follow Him.

But among the twelve disciples, Jesus was closest to John. During those years of ministry, John was Jesus’ best friend.

As for why we call Jesus rabbi, it’s in the verses you quoted. We don’t call each other rabbi, because we have one Teacher — Jesus. He is the Rabbi. We call Jesus our Rabbi, because He is.