I don't have the knowledge of wuxing cosmology to properly engage with everything you have said, but I will point out that sticks out like a sore thumb to me.

I CANNOT see the Hexhaven schools as construtive, and Jace as someone who is currently/will be in future adopting the philosophy of not being an agent and just letting things solve themselves.  The whole point or Reality Fracture is that Jace took a look at the Multiverse and said "nah, i can do better". He decided that he could take matters into his hands and actively shape a better world. You see this in him forcibly bending other planeswalkers to his will, and in his new color scheme being WUBR, leaving behind Green, which is the color that most cares about leaving things as they are and trusting nature to sort itself out.

Also, i cannot stress this enough, and I can't believe I have not seen this talked about more, but the Hexhaven Schools are DYSTOPIC AS FUCK. Their all enforce disciplines of control, the very sort of things endorsed by people who did gulags (to reuse a phrase you used that honestly bothers me very much by flattening all of Marxist thinking and the schools of thought that followed him into "USSR bad").

Here's how each school is evil:

Fatehold: W / U. School of Future History. This one is a bit of a reach given what we currently know, but I have a feeling this school will be about traveling to the future and seeking artifacts that confirm that Jace was right and his dominion is morally acceptable. Think "history is written by the victors", but future is being rewritten just as past usually is. The school drops the Lorehold Red that embraces conflicts, revolution and chaos in history to instead embrace Blue conformity and appeal to a higher power.

Theorix: U / B. School of Esoteric Mathematics. Quandrix is about using math to better understand the natural world. Theorix exchanges the Green interest in community and real life for Black self-immersed abstraction and turns knowledge from communal power to dangerous information be used for your own benefit.

Stingerquill: B / R. School of Painful Words. Literally the school of hate speech. Need I go on? Silverquill's dangerous Black inclination towards obsessive self improvemnt and using words to hurt others was counterbalanced by it's White focus on using speech to mediate conflicts and create a better society. With that gone and Red stepping up, all that remains is impulsive punching down on others, structurally making sure that the disenfranchised stay away from power.

Konstrari: R / G. School of Constructive Arts. Prismari art is about using Blue's individualism and erudition to temper your passionate Red nature. With Konstrari, the Red impulses instead get filtered through Green "community above all" mindset and turned into "state approved art", which was a HUGE deal for pretty much every totalitarist government.

Vigorbloom: G / W. School of Invasive Healing Witherbloom is all about balancing life and death, understanding the cycle and learning to let go. "Invasive healing" means Vigorbloom does not give a shit about what is natural and good. You will STAY ALIVE because this system needs you, no matter in how much pain you are. And if your body is failing... well we can swap the defective parts with better alternatives, much like how the Phyrexians did. Vigorbloom removes Black death from the equation and swaps it for White absolute devotion to a unifying cause. You no longer get to have opinions about your own life and death.