I Have recently finished reading multiple iBooks that have notes and highlights in them and am looking to clear up some storage on my iPad. If I delete the books from my iPad will the highlights and notes to the book still be saved if I redownload a book later? Thanks for the help.
iPad Air, iOS 9.2.1
If you've turned on "Sync Bookmarks and Notes", then I would expect your highlights and notes to be restored next time you download the book. See this article: https://support.apple.com/en-us/HT202759
You should probably test it out first to make sure you're good before you delete all your books. Find a book that doesn't have any highlights/notes and add some. Delete the book and then redownload. Hopefully your highlights and notes are still there.
iBooks notes and highlights
