Heh, another one in the 'I have no objectivity on these books because I read them when I was little' camp, here (not that I wasn't annoyed by plenty of stuff about them back then, not least Zelazny's very much of-his-time take on gender roles, poor princesses in Amber ...). I do see what you mean about the voices, or lack thereof, but I'm fond enough of Zelazny's Raymond Chandler-in-fantasyland idiom that I don't really object to its prevalence.

And it strikes me (though I haven't read the books for a while) that it might be defensible when it comes to Corwin in particular - and help explain why he works pretty well as a narrator - because, at least for most of this book, he really doesn't have any clear idea who he is, where he's from, or even where he is - as your quote highlights, in fact. So I can buy his code-switching being all over the place - and perhaps even Random's, given that Random goes out of his way to be the odd one out in many ways. But, yep, it's not exactly defensible in general, and it's worth noting that it works vastly less well when Zelazny isn't dealing with a hard boiled, vaguely Chandleresque protagonist like Corwin - I don't think I'm spoiling anything when I say that the 'Merlin' sequels to the Amber series are hugely inferior, and this certainly has something to do with it.

I can't help on the genre-name question, but I really like 'mannerist fantasy' as a term.

Oh, uh, also: hi! I think I'm delurking here.