The pronoun as a subject changes nothing in the adjective.
Rules: The regular adjectives in Norwegian get an -e in plural (i.e. when the subject is in plural, it does not matter if the subject is as noun or a pronoun). This is the rule when the adjective is separated from the subject by a verb like 'er,blir..' (= when the adjective is a predicative).
When the adjective is adjacent to the noun, it gets a bit more complicated.
Singular:
en stor bil
den store bilen (definite)
Plural:
store biler
de store bilene