Theres a lot of stuff youve posted and some of it is correct. (I knew Sinkankas through the Museum director and head gemologist for the Dupont Collection. He was a really good gem cutter and was given free reign through the Smithsonian to write several of his populr gemology books. I think hes been dead for a decade or more)
Nevertheless, we can all do name dropping and Id bore the **** out of you;
A pseudomorph IS and only is the chemical replacement of one mineral for another.Its done as "pyrite after limonite" or phosphoapatite after psilomelane"/Tho say a pyritized fossil is a "Brachiopod replaced by pyrite" is idiotic and meaningless. Its apples and oranges. The fossil species remains the same , its only been replaced by another salt(pyrite). The term , in your quotes, may have been incorrectly used to describe fossils that hve been remineralized. However that is wrong. There is no reason to describe a fossil as a "pseudomorph" of anything since its alreadydescribed and has not changed "Species"l . Fossil remineralization is commonly siliceous and can also be several other minerals including calcite/aragonite, phosphate, flourapatite from calcapatite (usually the first step in bone fossilization, sulphate and sulfosalt etc etc)
As I read to you and I will repeat. HERE IS THE OFFICIAL DEFINITION FROM THE AGI Glossary of Geology: Ed V
A mineral, whose outward crystal form is that of another crystal species, it has developed by alteration, substitution,encrustation, or paramorphism.A pseudomorph is described as being "after" the mineral whose outward form it has'eg quartz after flourite
In the geosciences (including paleo) we get pretty persnickety about misuse of terminology and jargon. So you may drop terms all you wish and name drop even more and the term pseudomorph does not change to suit your desires. Might I suggest that the real word you are searching for is "Petrifaction" or "petrification". Those terms, used interchangeably, specifically refer to entire "bodies" of the organism (or plant) whose substance has been altered or substituted by a mineral (like those I identified above)
A fossil is a cast, an ichnofossil, a sole mark, a mold,a C13/12 ratio cast, an alteration or a petrification. Each of those has a specific meaning to geoscientists, as does a pseudomorph.
Let John RIP, he wasnt a scientist, he was a popular writer for hobbyists and a hell of a good gem carver and auctioneer.