which of them are from a grammatical one

[EngLearner]

I created a thread in which there were five sentences, and I asked there which of them were correct. Someone named A replied to my thread, and then I (named B) replied to them. We had the following dialog.

A: "Correct in what way? From a grammatical perspective, or a colloquial one?"

B: "I'd like to know which of them are correct from a colloquial perspective and which of them are from a grammatical one."

I wonder if the bolded "are" is optional here.

 

[teechar]

No. Take out that "are", and you can even remove the second "of them".

 

[jutfrank]

I say no too. It has to stay there.

 

[EngLearner]

As far as I can tell, @teechar suggested the following versions (he said that I can remove the second "are", as in version #1, and that I can remove both the second "are" and the second "of them", as in version #2):

1. I'd like to know which of them are correct from a colloquial perspective and which of them from a grammatical one.

2. I'd like to know which of them are correct from a colloquial perspective and which from a grammatical one.

I say no too. It has to stay there.

What do you mean by "too"? If, as you say, the bolded "are" cannot be omitted, then you and @teechar disagree. I think @teechar said "no", but he actually meant "yes."

Am I missing something?

 

[jutfrank]

Am I missing something?

No, you've understood correctly.

teechar and I are both saying it's not optional (that was your question) but he's saying that you should remove the 'are' and I'm saying that you should leave it in place.