Their is a possessive pronoun, the third person plural. The pronoun their can be use as the subject or the object of a sentence.
The word us is the first person plural objective case pronoun.
The word 'or' is not a pronoun; or is a conjunction, a preposition, or a noun.
Whoever is a subjective pronoun.
"That" is a demonstrative pronoun. You "demonstrate" which thing you mean.
Those is a demonstrative pronoun, along with this, that, these, and such.
Pronoun
The pronoun 'that' is a demonstrative pronoun; a word to indicate, to show, to point to. The pronoun 'that' is also a relative pronoun; a word that introduces a relative clause. Examples:Demonstrative pronoun: That is my favorite movie.Relative pronoun: This is the movie that I like.The word 'that' is also and adjective, an adverb, and a conjunction.
a indefinite pronoun
The pronoun where is an interrogative pronoun, a word used to ask a question. Where takes the place of the noun that is the answer to the question. Example:Where are my keys? Your keys are on the counter.
A word that describes a noun or pronoun is an ADJECTIVE.
The pronoun 'what' is an interrogative pronoun, a word that introduces a question and can also function as a relative pronoun that introduces a relative clause. Example:What did he do? He did what you told him.
The pronoun 'one' is an indefinite pronoun and has no antecedent. The indefinite pronoun 'one' is a word for any person in general.In the sentences, "One should be cautious.:" the pronoun 'one' means anyone.Note: The word 'one' is also a noun and an adjective.