Words like Adjectives and auxiliaries function as MODIFIERS (M) in the phrase. They give us extra information about the headword, usually by narrowing down its meaning to make it more specific.
The modifiers in these sentences answer the question "What kind of people?"
Theoretically, there is no limit to the number of modifiers we can add to a phrase, but too many can be hard to understand or stylistically unpleasing. Sentence (5) below has an acceptable number.
Note that determiners function as modifiers. In the first NP, "some" has a narrowing function, separating a subset of sophisticated baby elephants from all the baby elephants in the universe. Likewise "those buns" in NP2 is a particular subset which the speaker wishes to identify.
In NP1 we also have a Noun "baby" functioning as a modifier. Historically, Adjectives often develop out of Nouns. This is one reason why there are so many word-forms in English which can be both Nouns and Adjectives, as in: