Everytime I research the terms "FF8 bradygames" on Google, this page pops up in the first 10... everytime... And yet you've never gotten a definitive answer.
YES. There WAS a FAQ/Errata list on Bradygames, as alluded to on the final page of the walkthrough, in the section "Ultimecia Awaits". The last sentence in the walkthrough reads "If you need additional help, check out the BradyGAMES website at www.bradygames.com for a helpful FAQ. Good luck and enjoy the incredible ending. You've certainly earned it!"
But what the, there is no FAQ/Errata on Bradygames' website! There was a cool Minisite created which showcased information from the book's characters, GF and bestiary sections but it was removed in 2002. The FAQ/Errata page was only updated once. It contained a list of original questions between 1999 and 2001 and in 2001 it was updated and the page lasted on Bradygames' website until 2004.
Luckily, YES, the page is still available. But not from Bradygames, rather, from the Internet Archives cache of Bradygames' website.
Here is a link to the very last (and most current) page, right before it was removed in 2004: https://web.archive.org/web/20040618135525/http://www.bradygames.com/updates/ff8faq.html
You can copy all of the text and either paste it to Notepad or just print selected. I have a copy printed which I keep as a supplement to the guide, seeing, officially, that's what the book mentioned was available. ...And seeing it's no longer available it makes having it more worthwhile.
Here's is a link to what the Archives have available from the old Bradygames FF8 Minisite. It isn't much, but it's a start. I think have a complete copy saved on the computer somewhere...:
https:// web.archive.org/web/ * /http:// www.bradygames.com/minisite/ff8/*
(There's no space in between the star and the slashes. I had to write it like that because the link was formatted incorrectly within the post.)
And here's a link to where the FF8 guide was the main page feature:
Hope this helps complete your guide!