The Breathing Universe Model (BUM) describes the cosmos not as a static geometry but as a living tension field that cyclically exchanges energy between expansive, contractive, and neutral phases. It generalizes Einstein’s constant c^2 into a dynamic vacuum tension H(t), preserving relativity while revealing the rhythm that sustains it. This paper reassesses feasibility in three layers: (i) theoretical coherence (closed equations, limits to GR/QFT), (ii) empirical testability (distinct predictions in H(z), w(z), and GW spectra), and (iii) integration with established physics (no ad-hoc entities; Ω-field coherence). Using factor analysis, cross-disciplinary alignment, and a Bayesian “smoke-test” plan, we find BUM to be theoretically robust, falsifiable with near-term data, and already qualitatively compatible with weak oscillatory hints. If confirmed, BUM would unify cosmic acceleration, dark-energy phenomenology, and the origin of time under one principle: the universe conserves energy by breathing, not by standing still.