You used an Amazon tool to create an ebook for the Amazon ecosystem.
It would make sense to use a B&N tool to create an ebook for the B&N ecosystem.
The magic word for fixed-layout at B&N is "PagePerfect". That should probably get you on the right track, you may not need to deal with epub at all.
jmurphy,

Thank you for your response. I've been looking for something like this. In my research, last night, I ran across something called "Kids ePIB" that seemed to be the equivalent of Kindle Kids Book Creator. I don't know where to look for these tools, however. I try not to expect the folks here to do the work for me but I Googled both of these tools by name in addition to searching the B&N site under Author Tools and Tips and Self Publishing Services and there's nothing. How well-hidden is this tool you're referencing, here? If you have a link, that would be fantastic. Thank you, again.
jmurphy,


Thank you for your response. I’ve been searching for something like this. Last night, I read an article that mentioned “Kids ePIB” which sounded like it could be somewhat equivalent to Kindle kids book creator. I searched all of Google, though, for this tool and the one you suggested, here, with no results. I also went to B&N Author Resources and looked under Author Tools and Tips and Self Publishing Services with nothing there, either. I don’t want to expect the folks here to do the work for me but just how hard is it to find this tool that you're referencing, here? A link would be awesome. Thank you, again.
I suspect jmurphy's suggestion of PagePerfect is your best bet if you can find it, but short of that, you can use calibre to convert amazon formats to EPUB. kindleunpack can also be used to do the conversion. I use kindleunpack from the command line, but it is also available as a calibre plugin
Sorry, Brian. All I know is that PagePerfect is a thing. That appears to be the name of the format, not the name of the tool. Does B&N have support forums, or a method of opening a ticket? Other than that I'm out of ideas, sorry.
middle of the page:

https://ebookpartnership.com/fixed-layout-file-formats/
I looked at the sample of the book from Amazon. Unpacking the file with KindleUnpack gave me a collection of images for each page. I stuffed the images into an epub file using Sigil and added one image with a svg wrapper per xhtml file. Pretty much a minimal effort conversion.

Looking at the file I created on my Kobo Sage, one reason that this book is not available on eInk Kindles is that the text size (looking at About the Music) is below 4mm. Looking at the margins on the pages, the images could be trimmed to improve the text size.
From that page:


j.p.s.

Thank you. The idea of converting the MOBI file that I created for KDP to an EPUB, using Calibre, is a clever idea that sounded promising. However, again, that did not work, either. I'm going to have to look into the kindleunpack as a Calibre plugin.

jmurphy,

Thank you, again, for hanging in here with me. I did start a B&N support ticket. However, the ticket was regarding one of my earlier issues about an error message that I received in my first upload attempt. Nevertheless, I have not heard back yet. The way I wound up here was that the help article and video that B&N put together actually directed me to this forum. They actually posted a link directly to here. Apparently, the person who put together the help article is one of the moderators here?
Dr Drib,

I was excited to check this out but jhowell indicated that you must have a Publisher account?

DNSB,

Did you actually solve this!?! It's getting late, now, so I'll have to look at this at the start of my day, tomorrow, but this is looking promising!! I see what you mean about the margins. Part of that problem was caused by the fact that KDP required larger margins for the paperback version and I inadvertently wound up using that same file for the Kindle. I used Adobe Acrobat Pro to increase those margins. Perhaps I can use Acrobat to make them smaller as well.