Reduced Proxy Study of Action-Driven Localized BVP Targets for Exchange-Symmetric Brane Segregation

The first V. E. R. A. preprint formulated symmetric cross-brane baryon segregation as a conservative five-dimensional effective framework: elementary events deposit B on one brane and anti-B on a reciprocal brane, preserving the total two-brane baryon charge. This exploratory follow- up is a reduced proxy study. It asks whether the stochastic critical-domain picture can be connected to a more explicit localized effective action without introducing a permanent source bias. We construct a reduced completion chain combining a baryon-preserving scalar-diquark contact, reciprocal matching, localized neutral-sector profiles, stochastic thin-wall domain growth, a non-thermal drain closure, and conserved-stress geometry diagnostics. The strongest result is a non-empty action-driven target branch near T ≃ 131. 7 GeV, with small reduced BVP backreaction, large effective event rates, controlled localized profiles, and viable stochastic nucleation under explicit efficiency assumptions. A gate-derived coupled transition BVP further sharpens the geometry requirement: the critical/odd-spurion stress survives only in a radiation-like conserved branch. The result is not a completed baryogenesis model and does not predict the observed etaB. Instead, it identifies quantitative completion targets: derive the required visible survival/dilution factor, obtain observable-domain coherence, replace proxy phenomenological filters with recasts, and promote the reduced drain, carrier, mediator, radion, and stress sectors to a full finite-temperature five-dimensional transport solve.