Plural of "I am nobody important" i.e. "we are important"

In the first group of two possibilities the English is not standard.

Second group of 3 possibilities

In "1" the use of "we" connotes the use of "we" as the representative "we" and carries therefore some ambiguity. "2" seems not very natural and "3" is not idiomatic (ref.).

If instead of "none" "neither" was used, it seems that "3" would be the best choice.

• Neither of us is anyone important.

There is an idiomatic expression that came to mind, when I read the question, which I think works perfectly well, and is grammatical. It is; however, rather informal but it rolls off the tongue

We're just a bunch of nobodies

It's even in a book title about the founders of Wikipedia

How a Bunch of Nobodies
Created the World's
Greatest Encyclopedia

Being a "nobody" implies the person is unimportant, it's understood, there's no need to modify the nobodies with "important". According to the American corpus on Google Ngram, the expression "of nobodies" is more popular, at least in its written form, than "nobody" or "no one important".

"I am not the person that is important."

"I am not the important person ['here']."

"We are not (the) people that are important."

"We are not the important people."

From memory, if that helps.

I'll start with your examples:

"We are no-ones important"?
"We are nobodies important"?

These are wrong. The first example could even sound like you are describing yourself as "no-ones", but no-ones who are important (if there was a comma after "no-ones").

We are not anyone important
We are no one important

We and anyone/no one clash here. It sounds like a hive-mind speaking.

None of us is anyone important.

This emphasises that, for each person in the group, it is true of all of them that they are not individually important.

So what else could you say?

I would say:

"We are not important"

or

"We are not important people"

Depending on the emphasis you want, other options include:

"We are not (the )important people" "We are not (the )people who are important"

These options imply that, although we are not important, other people might be (e.g. "We are not the important people, they are".)
Or, depending on how it's stressed, it could be emphasising that although we're not important people, we're instead something else (e.g. "We are not the important people, but we are the rich ones")

"We are unimportant people"
"We are unimportant nobodies"

These options remove that emphasis, by using "unimportant" instead.

Of course, to make it more informal, you can replace "We are" with "We're" in all cases

If someone asked us "Who are you people/guys?" it wouldn't sound wrong for me to say "nobody important".
You could also say "we are no one in particular".

You can get around the problem of the questionable arity of "nobody" by using an alternative phrase like "none of us", which is explicitly singular.

"None of us is important" is probably the most grammatically correct rendering of the idea, but it's not a perfect semantic match to the original sentence(s).

"None of us is anyone important" is a bit better of a semantic match, but it's awkward.

"We each are nobody important" is the best semantic match, but nobody would ever actually say that.

Ultimately though the original sentences were not about none of the people present being important, but instead the fact that it was not important for the second person to know who anyone in the first group of people is. Therefore to match the intent of the original sentences, I would probably say something like "It's not important for you to know the identity of any of us."

"We're no-one important".

"We're" is plural.

"No-one" is not numbered. Who is here? "No-one". That doesn't carry a number. "Nobody" is numbered. "Not one body". I admit it is counter-intuitive.

Alternative answer: "We are not important". (As simonalexander2005 said).

I suggest that Question is much more important than it seems…

Decapitated Soul Posted the most useful response and even that came hardly halfway close.

Before reading all the above I was thinking of Posting that perhaps there should be but sadly there isn't a way of saying that in English.

After reading the above, I'm convinced that's true. English simply does not recognise that concept.

Please consider the I/we, single/plural dichotomy that so often crops up in ELU, EL Learners and other fora. IE, is it OK to use "they" in place of "he or she"?

Again, consider the dropping of medieval "thee, thou, you" for modern "you." Did that dropping help, or hinder precise communication?

One of the difficulties is in identifying whether nobody/ies is being used as a noun or pronoun.

I have two Chambers dictionaries and a Chambers Thesaurus, a Roget's Thesaurus, and a Roget's International Thesaurus, published in 1973, 1992, 1992, 1973, and 1979 respectively, and none of them cite nobody as a pronoun, though they all mention or imply all the meanings we know.

Online, Dictionary.com and the OED has nobody as a noun and pronoun, and the OED even cites it as a complement, though I see little to no difference in the use in the OED between the examples for noun and those for complement.