Sure the first three are inseparable, However it is when sin enters the picture that a believer has the most likely opportunity to leave the christian life/walk.
Romans 6, the beleiver is dead to "living any longer" sin. Dead means dead. Sin means sin. Living any longer means known for that sin. A believer cannot be known to be living, acting, thinking, (the state of present continuous) a particular sin.
Not perfectionism, (see 1 John) as otherwise you would be deceived and/or a deceiver. But not known to be in sin. So sin is the key.