Pronouns

The pronouns in the sentence are:

• everyone, indefinite pronoun, subject of the sentence
• who, relative pronoun, introduces the relative clause 'who heard the news'

No, the word THESE is functioning as an adjective(describing the noun 'scarves') not a pronoun. The sentence is an interrogative sentence (a question).

The pronoun 'these' is a demonstrative pronoun, a word that takes the place of a noun in a sentence indicating near or far in place or time.

Example: Which of these is the scarf Mom said she wanted.

The pronoun WHICH is an interrogative pronoun, a word that introduces an interrogative sentence (a question).

The pronoun 'most' is an indefinite pronoun, a word that takes the place of a noun for an unknown or unnamed number or amount.

The word 'few' is also an indefinite pronoun.

Note: The words 'most' and 'few' are adjectives when placed before a noun to describe that noun; for example, 'A few dresses are mine." and "The most dresses are hers."

There is no demonstrative pronoun in the given sentence.

A demonstrative pronoun takes the place of a noun, indicating near or far in place or time.

The demonstrative pronouns are: this, that, these, those.

Examples:

She did that to protect herself.

She should do this to protect herself.

The pronouns in the sentence are:

• what, an interrogative pronoun, used to introduce a question. The interrogative pronouns are: who, whom, what, which, whose.
  
• she, a personal pronoun, a word that takes the place of a noun for a female as the subject of the sentence or a clause;
• herself, a reflexive pronoun, a word that 'reflects back' to its antecedent. The reflexive pronouns are: myself, yourself, himself, herself, itself, ourselves, yourselves, themselves.

The pronoun 'that' is functioning as a relative pronoun, introducing the relative clause 'that will be most useful'.

The relative clause is providing information 'relating' to its antecedent, 'documents'.