Perhaps you do give Harris too much credit, but your allegorization of the characters makes a lot of sense. And as we were taught in high school, anything conducive to "symbolic" meanings is literature, and anything not . . . is not.
In particular, your point about Zinaida and "primitive accumulation" is just beautiful. As you obviously remember, back when the existence of a natural-resource-looting, ex-KGB-employing bank mafia became undeniable, it was not the Marxists but the Westernizing forces--the Anatoly Chubaises of the world--who used the "primitive accumulation" trope to explain it away as a natural and transitory stage.
While we're on the subject of literary stereotyping, my favorite instance from le Carré is Yevgeny's praise for his native Mingrelia:
Mingrelian peoples are pure peoples. Other Georgians got so many invasions they don't know if their grandmothers was raped by Turks, Daghestanis or Persians. Mingrelians was smart peoples. They protect their valleys. Lock up their women. Get them pregnant first. Got brown hair, not black.
As Miss Malaprop said: Men can be such Bavarians! This kind of stage-ethnicity is something that's never bothered me too much, but certainly it results in malapropism-barrages unheard-of outside "The Family Circus."
Any unfinished business? Yes, we have to cast le Carré. Nigel Hawthorne as Tiger Single. Colin Firth as Oliver. Ben Kingsley as Yevgeny. For Aggie, whoever the tallest actress in Trainspotting is.
Your last letter made me laugh and laugh. We'll have to pursue this later.