This paper presents a unified phenomenological synthesis of the MyominAung Photon-Sea Theory (MATE), demonstrating how a wide range of gravitational and cosmological observations emerge from a single medium-based framework. Treating the vacuum as a physical photon-sea with frequency-dependent refractive and dissipative properties, the work reproduces classic Solar System tests, galactic rotation curves, binary pulsar orbital decay, multi-messenger timing delays, and key cosmological anomalies without invoking spacetime curvature, dark matter particles, or dark energy.Serving as a master phenomenology paper, this work consolidates and links a series of focused companion studies, providing a coherent observational narrative spanning Solar System physics to cosmology. It establishes MATE as a minimal, falsifiable alternative framework grounded in physical medium dynamics rather than geometric gravity, and functions as a bridge between the MATE Master Equation and its observational consequences.This record is a supplementary phenomenological synthesis to the MATE Master Equation and is intended to be cited alongside the parent theoretical formulation. This work is supported by the following Parent-2 series studies: • v1.2.5 – Binary Pulsar Orbital Decay as a Photon-Sea Dissipation Process • v1.2.6 – Resolving the Hubble Tension through Photon-Sea Resistance • v1.2.7 – Numerical Analysis of the GW170817 Time Delay within the MyominAung Photon-Sea Framework • v1.2.8 – (forthcoming) and subsequent Parent-2 validaon studies. These studies constitute the phenomenological validation series of the MATE Master Equation (Parent-2), each addressing independent observational regimes while sharing a common theoretical foundation.