I am writing a novel, but I have a few questions about how the publishing industry deals with a few things. These are issues that are important for a part of the novel and I want to be as realistic as possible. So any help would be great. In the story a major publisher really likes it, but gives it to their sister publisher that handles new or unknown authors.

1. Do publishers actually read anything that is sent in unsolicited, and do they read the whole thing or just some of it?
2. Would a small publisher offer an advance, and if so how much?
3. How much would a typical author make on books sales?
Any help would be much appreciated.
Thanks,
Brett