Using LR 6 with Win 10, I created three separate saved books each in a separate collection. I wish to combine them into one for Blurb printing. Each separate book has a different image layout which I wish to retain in the combined version. I am able to combine the images into one collection in the Book module, however, the separate and differing layouts were not retained. Can this be done, i.e. create one new book but with the unique previously created templates?.
The easiest method is to save the pages layouts as custom pages. You can add them to favorites. You can then select your preferred layout from favorites and click add page. Then drag and drop your photo. The books must be the same size and format as custom pages are obviously saved in LR prefs based on book type and page size.