Hello Arriane,
I've been working with my brother for several years on editing and publishing his works. Our experience (prior to starting our own company) might be of some use...
Last question first: I'm not sure how the big five work. One consistent theme I've run across in author's blogs is "teams."
An editing team, (composed of a developmental editor and several peons) develops the content of the book, working through the various stages of editing that you mentioned.
An art team designs the internal and external appearance of the book, crafting cover art that fits both the book and the market. (Remember, cover art might be the number one selling factor of a book, so in the publisher's view, this team is probably going to be just as important as the editing team.)
Then you have a marketing team, which creates channels for book sales, promotions, etc.
From what I've gathered, much of the book development process is the coordination (or lack thereof) of the various teams working on the book.
Now, back to the question: do well-known authors get more leeway? Probably. If you want evidence of that, just look at Patrick Rothfuss or George R. R. Martin. Martin recently delayed his next book release for the five hundredth time, despite having multiple legal contracts that said otherwise. If he was just a midlist author instead of one of the best known authors on the planet? I'm guessing his publisher would have dropped him in a heartbeat. And probably fed him to the sharks as a warning to other upstart writers, while they were at it.
As far as the stages of editing, those depend on two things:
1. The publisher's editing style. All publishers maintain an in-house editing style, and so I would say that their editing process must be individual to both the publisher and the book as well. Some books need months or years of editing to produce a polished product. Others require far less work. Terry Goodkind claims that he submits his novels as nearly finished products, with only very minor revision necessary before publication.
2. The printing method the publisher employs. Digital printing is the realm of self-pubs, but many smaller publishing houses are now using it as well. Because they don't have much (if any) standing capital, the lack of initial investment in a book is worth the greater per-unit price. Traditional publishers, on the other hand, use traditional offset printing, which the requires the creation of an actual physical printing medium. (It's the modern version of those big wooden blocks that monks once carved letters into by hand). Traditional offset is expensive initially, but it produces individual books at around a third of the cost, so in the long run, it's much more cost effective.
Apologies, getting to the point now... Traditional offset printing requires the creation of very expensive "book plates." Once these physical plates are created, it's very expensive to create new ones, so your author can no longer make changes to his book.
However, with a small publisher using digital printing, there's only an electronic file. Making a change to the book is as simple as resubmitting the file, and costs almost nothing. The only real limitation is how much headache the publisher is willing to put up with.
I apologize for the length of this post, but I hope it was helpful! If anyone can correct anything I've said, please do.
Best of luck!
(P.S. If you own one of Butcher's books, then you're familiar with traditional offset printing. If you want to see an example of a digitally published book, look here:
http://www.amazon.com/Sidewinder-Daniel-Stephen-Foster/dp/1941842003/ref=sr_1_1?ie=UTF8&qid=1452101969&sr=8-1&keywords=Sidewinder+foster)
