Brooklyn does a little of both. He'll work with a writer, really testing them out for a while, and then may decide the relationship may not work. However, it could also work out the other way, with Tranquility Base being an example of this.
Two? Absolutely not. Try, like, ten. And you better be ready to toss around multiple ideas, including ones you've already mapped out completely. He's a nice guy, but tough in a room.