I'm pretty sure that a professional author was involved somewhere. Some of the scenes described in the book are a little hard to swallow. The imagery is a little too descriptive at times and the writing style changes ever so subtly during those periods. Nothing major, but certainly noticeable over the course of the book, and enough to detract from the organic-ness of it. I could be wrong though, but thats how it seemed to me. Plus he spends a lot of time pissing around describing little events that really dont need to be described, or certainly not in the amount of excessive detail which he does. It slows the story and I found myself skimming through the pages more than once.
I put your first point down to a professional editor as much as the involvement of another author but you could be right. I did English Lit O-level 22 years ago and have avoided analysing books too much since. He does ramble on occasion too I agree, although the 5-6 pages devoted to the honey badger culminated in my laughing so much I couldn't read for tears. It's all subjective of course.