The dance crew, after performing for the crowd, wash the paint from their faces.

which subject-verb agreement rule applies to this sentence?

use a singular verb with a singular subject
use a plural verb with a plural subject
use a plural verb with a collective subject functioning as individual parts
use a singular verb with a collective subject functioning as a unit

I believe the best option to be the third one: use a plural verb with a collective subject functioning as individual parts.

Explanation:

The subject of the sentence we are studying here is "the dance crew". The word "crew" is singular and, because of that, we would expect the verb to conjugated in the singular form as well - "washes". However, since "crew" is a collective noun - it indicates a collection or a number of things or people -, there are two possible ways to conjugate verbs with it. If we think of crew as a unit, the verb shall be singular. But, if we think of it as the individuals who are part of, each one of them performing an action, then the verb shall be in the plural form.

In conclusion, if the verb is in its plural form - "wash" -, the best explanation for its subject-verb agreement is the third option:

use a plural verb with a collective subject functioning as individual parts

hmm, sadly there is no dialogue. there is no place in the story where he is talking to anyone. it's more of just describing what he eats and where he sleeps. you have to become anne frank, give details of where you are, what other folks look like, how the environment is. have a little bit of dialogue tell of what people are specifically saying. anne frank talked about her entire household including the people, the objects, the lighting, the food they ate, and even the smell in the air. there has to be more to your diary entries, the whole story in its current state is only about peter van daan, the food, the sounds, and where he sleeps. also he seems to be writing only once a year yet more than that happened from day to day. for a friend, i can you write it out, if you want.