The heroes are students (WHO are) all very different

[gwada]

Hello,
I am having trouble figuring out whether the use of WHO is mandatory in the following sentence:
"The heroes are students (WHO are) all very different. Still, they have to get along because they sing together in the school choir."
Could the part in bold be omitted? (Such as in sentences like: "The man (who is) in the street is not my brother")

I would feel uncomfortable doing so, because "different" is an adjective. So it has to work either as epithet, or attributive. But I am not sure that I am right about that.
To me, omitting that part in the first sentence would only be possible this way:
"The heroes are students, all of them very different. Still, they have to..."
Thanks for helping me out.
Have a nice day.

 

[Tarheel]

*The heroes are students who are all very different.*

Take out "who are" and you get: "The heroes are students all very different."

I don't think so.

 

[gwada]

Thanks a lot for helping me.
It sounded weird to me too, but someone told me that was a viable option.
Thanks for confirming that it is not.
Have a nice day.

 

[Tarheel]

If you want to know if a word or phrase is necessary to a sentence simply take it out. If the sentence doesn't hold together then put it back in.