I am facing some concept doubts.

1. He is among those who are the best players.

2. He is among those, who is the best player.

3. He is the one of those who are the best players.

4. He is only one among those who are the best players.

5. He is only one among those who is the best player.

My question:
Are all these sentences correct? If not, how should I write?
Thanks.