Good Argument.
I differ in my perception on the issue of education. I can see the proles serving in educational roles, purely based on the demand for educators. Looking at the primary and Secondary educational systems. I don't see an intendant being a primary school teacher, while we can see the humor of a Psionic teacher in a a rowdy classroom. Clearly the benefit is form a the use of psionic in cognitive therapy or redirection would exceed the RL success in such modalities. while you have recognized ambition as being a core value of Zhodani society, and further you and I agree that aptitude and ability are evaluated early on within Zhodani society early on I can see Proles in educational roles both academic and technical.
Given the statistical probability of a proles having a specialized aptitude in any given field it would be to the benefit of Zhodani society to not only encourage, but to facilitate such an individuals pursuit of developing such potential wether it be in Science, Mechanics, Engineering, Medicine, Education, etc...
Also we can take into account that the Zhodani society has developed psychology to a level here in RL we could hardly imagine... There is the ability even now to read non-verbal ques (attachment based therapy) such as: physical signs; gestures; biofeedback; and etc... A Prole can be effective when trained in such a manner. I imagine that non-psionic merchant crews would need to be trained in such a manner to deal with human cultures outside of the consulate.
Anyway that is my take on education.
As said before, I expect Zhodani, due to their psycological view of the society, would give uttermost importance to education, moslty in early ages, as is where they can not only identify the talents (not only in psi, but also in other fields) and inclinations of their children, but also the traumas and other mental disorders that may be treated (or must be watched) on them.
I agree about secondary education, and even more about higher one, can be taken over by proles. After all, to train an engineer I guess mathematical talent is more important than being a good telepath, to put an example. That's why I said that in secondary education (or its equivalent, I don't know the Zhodani educational cycles) would not be so personalized as primary school, at least for the proles (again, hence the EDU limits on initial stats).
As far as capital moving through the consulate I speculate it may be something based loosely on the notion of Edward Bellmy's
Looking Backward which embraces the
Rochdale Principles. This however raises an issue in conflict with the idea of ambition and advancement? Do such values manifest in economic and personal wealth terms or is this instinct or drive moderated or mediated by the use of psionic in the consulate?
First of all, I didn't know those books, and just the Wikipedia articles you gave us seem quite interesting.
I agree with you about how Zhodani society may handle (at large) economy, but OTOH they sure have rewards for succesful individuals, be them in prestige, status (not necessary social), fame, respect, promotion or whatever it could be (incluiding increased earnings or privileges). Reward uses to be an important part of the human (and non human) motivation, and sure they know it, whatever the reward is.
That's why I think proles can raise to the higher strata of the society (and the use of psioics and psycology will avoid
Peter Principle to be, so leading to higher efficiency).
Being noble or not is another matter, I see Zhodani seeing nobleship aside from status, as dificult as this may be to undertand for us (and I'm not sure to be able to explain myself here, and language has little to do in this).
As I understand them, a succesful merchant, or teacher, or doctor or whatever it is can be seen for them in the same respect that a noble, though it's understood by the society as doing different roles, and they probably don't see any contradiction in this.
The proles understand they have no vote, though they know their wills are known and taken into consideration (that's part of the Tavrchedl' mission, nearlyu as important as to identify troubled people). In a way, it's like in Starship Troopers difference among citizens and contributors, with only citizens having vote rights (with the difference that on it you can apply for a job that would end up with you being citizen).
Even so, they see the proles responsabilities as being equally important to the society, and a successful prole may be as proud of his/her post as any successful noble.
Of course, YMMV.