Phenomenology of Open Cosmological Systems: An Observational Roadmap for the Dark Sector, Black Hole Thermodynamics, and Early Universe Physics

Theoretical frameworks invoking Open System Thermodynamics and Brane-Bulk coupling [Frisina, Zenodo 2026, Papers I-V] offer a unified resolution to the fundamental tensions of the Standard Model (Lambda-CDM). However, theoretical consistency is a necessary but insufficient condition for scientific validity. In this work, we translate the geometric mechanisms of the "Omega Framework" (Topological Decoupling, Shadow Brane projection, Flux Injection) into a rigorous set of falsifiable observational signatures. We present a Falsifiability Matrix comparing Lambda-CDM predictions against Open System predictions across three physical regimes: Gravitational Wave Astronomy, Large Scale Structure, and Precision Metrology. We derive explicit transfer functions for post-merger gravitational echoes (identifying a detection threshold for horizon reflectivity R > 0.01), the modified growth index gamma(z) for early galaxy formation (JWST), and the specific dipole anisotropy expected in the CMB. Crucially, we define exclusion criteria for Dark Matter direct detection, distinguishing between standard WIMPs (predicted null) and geometric/axionic signatures. This paper serves as an operational roadmap for experimentalists to validate the multiverse hypothesis.