Yes, it would, although maybe he's just saying Wolfe refers to anything and everything and has picked some extreme examples, like Polonius ends his list of things the players in Hamlet can perform with `scene individable and poem unlimited', whatever that means. But it's fun to make dodgy hypotheses based on tenuous connections.
Plato, I suppose, means the ideal republic of the Republic, with its philosopher ruler, which isn't so far off what the autarch is (in practice, I mean, when we actually meet him --- pedants will want to wreck this by noting that we don't in Shadow, apart from an appearance in the House Azure which isn't explained till later). You could probably make an argument that the New Sun was the Form of the Good, but that would be a bit vague even for my taste. Nor does it seem particularly outr'e to suggest the Commonwealth is less than ideal. Was he thinking of cave dwellers, looking at the world in shadow? Or (I may well be doing Budrys a disservice) does Plato mean `some Greek guy with old-fashioned ideas about society'?
As for the others --- neither aristocratic debauchery and perversion, nor the systematic murder of prostitutes are major themes in Wolfe, although I hesitate in case anyone has a piece of fan fiction ready. Here's my guess: both de Sade and Jack the Ripper are generic references to a decadent (in Wolfe's case `decayed' would seem more appropriate) world of aristocratic (i.e. exultant) vice --- we already know in `Shadow', for example, that Thecla and her relatives are concubines.
There was a 1979 film, `Murder by Decree', in which Jack the Ripper turned out to be the Duke of Clarence, mad son of Victoria and Albert (there, I've spoilt it for you, sorry); the case was investigated by Sherlock Holmes (Christopher Plummer) and Dr Watson (James Mason). They managed to cram the freemasons, and even werewolves if the quote below is anything to go by (though I can't remember that bit), into the story, too. `Oliver Stone would love this plot' is a comment in the IMDB review (see
http://us.imdb.com/Title?0079592). Coming a year or so before Shadow of the Torturer, with a strange city (they always do that to Victorian London, but I suppose Dickens got there first), and a proto-Wolfean mixing of themes, it might have been enough to suggest to Budrys that `Shadow' had Jack-the-Ripper connotations.
Holmes: We've unmasked madmen, Watson, wielding sceptres. Reason run
riot. Justice howling at the moon.
corncrake