yes, in cases where you are using the word to point someone out such as "That character over there did that." where we are replacing the word person with the word character
the junior of two persons in age (often used with a possessive pronoun):
No, it is a verb. The word effect is used as the noun.
Of course !
Yes! In fact in the term "puppy chow", chow is used as a noun because puppy is the adjective that describes chow!