(Posting solely on my own behalf now 
)
This is an intricate and thoughtful schema, and I applaud your efforts try to verify COI, but it remains attestation, not verification–it still redounds to trust.
The only way to truly verify that there is no COI would be full doxxing of the delegate, every multisig signatory, every delegator, every referendum proponent, and anyone else with whom any of those parties have personal and/or business relationships.
Like you, I take conflicts of interest very seriously and I’m glad COI is a point of emphasis in the DVP, but the reality is that an ecosystem featuring anonymity and pseudonymity precludes verifiable COI and must, in the end, rely on some flavor of trust, regardless of how large an edifice one erects to obscure it.