: I have another example -- a small book by Peacock -- on my books page http://www.hxa.name/books/
. It includes a variety of bookish format features -- footnotes, poetry, various headings, small-caps, even greek text. It may be good for comparing readers.
On page-template.xpgt: I would consider it an isolated refinement for Adobe's reader(s). Other things -- authoring, packaging, etc. -- should not depend on it. It is minor. I have used it because the DigitalEditions defaults are a little weak in choosing column width and margin size.
On alternative stylesheets: epub explicitly mandates support.
On foreign content: epub explicitly does not mandate display of all/any unicode chars.
But we are dependent on reader-software/devices. And they will not all implement all the spec. For content projects, I, personally, would plan only around the core XHTML+CSS. Anything else has various amounts of risk.