I hadn't pictured Lloyd as Vincent Vega, but now that you mention it, I could see it. I think on another thread someone thought of Kirsten Dunst as Frannie, which I could also see. It's strange, I really don't picture any particular actors when I think of the novel. I'd be interested to see what others are thinking, though.
This is less about a specific actor, and more a general wish, but I think it would be cool if they cast a culturally Deaf actor in the role of Nick and altered the script a bit to incorporate ASL or just signed English. I think the adaptation could do some really complex work (without altering the general feel of the novel) by being conscious about the casting of Nick (like was done in A Quiet Place).