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I came across a question from an author...
As authors, we do not own any of the design elements of our books. So if we want to print or publish elsewhere we will have to have new illustrations, layout design and cover.
Yes and no, your contracts may allow you ownership of those copyrights - you paid for it you should own it. Being as it may, they changed their contracts on a whim. I don't know which one you got nor what rights you have or if they were established. I'm pretty sure the authors own all the content they've paid for and have implemented in the books they published. I'll update when I have a more concrete answer.