Can someone point out to me again a page or explain why these special
characters might not work in my xsl sheets? I see all kinds of xsl
advice around the web responding to questions using the characters
" &apos, etc, and yet I thought I remember reading that they were
non-standard?

XSL 1.0 / http://www.w3.org/1999/XSL/Transform

This is inherently supported from XML because XSLT *is* XML:
http://www.w3.org/TR/xml/#sec-predefined-ent