Questions about comrades (Early game minor spoilers)

So I'm a bit into Chapter 3, still early game, and I got two questions:

1. How do you send Greymanes to a place? I want to look at getting the quarry, but it's too much for just myself, and I read that I can send Greymanes to help. But after getting the camp, how do I do this exactly?

2. Regarding Damiane and eventually Oongka, I read that they seem superfluous and not really that relevant overall compared to Kliff. But can you make them more worthwhile? Like give them gear and even artifacts to get stronger with you?