My wife is an author with an MFA in Creative Writing, and advanced degrees in math, who has published both fiction and math textbooks, so I vicariously know a lot about publishing. The potential problem that exists with your otherwise reasonable plan is that many (all?) publishers will balk at pre published material. You're talking about material that's here, in ebooks, and on lulu, before it ever passes over the publisher's desk -- that could be a big problem, you need to look into it.