Re: PDF t9 Word keeping footnotes
Yes either Daisy, NIMAS or ePub is more likely to have appropriate markup for footnotes. I believe most textbooks in the US are supposed to be available in the NIMAS accessible format. The Braille Blaster program can convert NIMAS files directly into Braille documents. You can read a bit more about NIMAS at:
The Daisy and ePub standards are now pretty much merged, and since the Edge browser will act as a ePub reader, that might work for reviewing your documents if you can get them in that format. I believe that PDF documents that conform to PDF-UA should also have navigable footnotes. The problem with pdf is that it was initially designed to provide different printers with the ability to produce the same page output no matter the printer and accessibility needs were only added later when the US Government started supplying documents and forms in PDF.