We present Active Vacuum Emergent Geometry (AVEG), a discrete vacuum framework in which quantum phenomena, gravitation, and cosmological expansion emerge from a single underlying mechanism: topological admissibility and replication dynamics of an active vacuum network. In AVEG, spacetime is not a fundamental manifold, fields are not ontological primitives, and forces are not mediated entities. Instead, physical behavior arises from constraint-driven re-expression of discrete vacuum cells governed by admissibility closure, restoration stiffness, and replication plasticity. At microscopic scales, solitonic locking dominates, yielding stable particle-like excitations and an effective quantum description. Hilbert space, operators, superposition, tunneling, spin, exclusion, and atomic structure emerge as bookkeeping representations of admissibility relations rather than fundamental ontological entities. At macroscopic scales, replication dynamics dominate, producing cosmic expansion via sequential cell insertion rather than metric stretching. Gravity emerges as a bias induced by replication suppression gradients, reproducing General Relativity phenomenology without curvature as a fundamental construct. The framework accounts for key observational phenomena—including the Hubble law, gravitational lensing, galaxy rotation curves, the Bullet Cluster, gravitational waves, black hole horizons, Hawking radiation as horizon admissibility leakage, and baryon acoustic oscillations—without invoking dark matter, dark energy, or vacuum energy density. The BAO scale arises as a frozen geometric replication wavelength from an early high-plasticity vacuum phase. Black holes are described as regions of saturated admissibility rather than singularities or extreme matter density. AVEG preserves the empirical success of Quantum Mechanics, Quantum Field Theory, and General Relativity as effective descriptions while providing a unifying vacuum ontology beneath them. The theory makes falsifiable predictions, including density-dependent deviations from Newtonian gravity, higher-order lensing anomalies in cluster mergers, horizon fluctuation spectra, and subtle BAO non-Gaussianities. We conclude by outlining experimental tests, open mathematical challenges, and broader implications.Update (v0.2): Added Section 7.13 proposing a topological origin for the Fine-Structure Constant.