The contestants in the quiz show sat wth we,us audience members.

I think us because it is an object?

For we, us scientist, the discovery of a new planet would be exciting.

I think us?

3 answers

You are right for both.

How about these...
The ones who defeated the scary monster were Gerry and them/they.

I think they because it is a predicate pronoun,

The ballerinas featured in the show were Bernice and she/her.

I think she due to a predicate pronoun?

Yes. Both are correct.