No need to panic - your books are safe! All you have to do is log in to your new device and download your books - all of them will be listed as owned, so no additional payment will be necessary.
Unfortunately, due to security reasons, it is currently not possible to import any files (books or chess databases) into the app. Please note that we use a special format for ebooks here at Forward Chess (it's how we get all the interactive elements in there) and book purchases from other devices like Kindle, Nook, etc. aren't compatible with that.
Unfortunately, it is not currently possible to import chess databases (PGN, CBH, etc) into the app.
No. Allowing Forward Chess to work on jailbroken iOS devices would be a violation of our contractual obligations.