Unified Multifrequency Resonance Theory (UMRT) proposes a unified framework in which gravity, the Standard Model of particle physics, dark matter, dark energy, and cosmological evolution emerge from a single multicomponent vibrational scalar field called Psi_total with a small number of components (N=3 baseline, extensible to 6) and one dominant nonlinear coupling lambda_nl. The baseline oscillation Psi_total_0 at near Planck frequencies (omega_i ~ 1/l_P) undergoes frequency interference and resonance cascades due to small detunings delta_i. These macroscopic frequency differences Delta_omega_ij dynamically generate fermion mass hierarchies (via exponentially suppressed effective Yukawa couplings), gauge symmetries through rotations of the component triplet on a compact internal S^3 manifold (yielding SU(3)_c adjoints and anomaly cancellation via vibrino loops), fuzzy black hole cores through soliton-like diffusion, hybrid dark matter halo profiles with exponential cores (~1-2 kpc) and destructive interference suppressing subhalos below ~10^8 solar masses, and late-time dark energy from differential decoherence (w(z)~-1 + 0.05z) UMRT resolves classical singularities via quantum diffusion, the missing satellites problem more robustly than single-field fuzzy dark matter or standard CDM, the matter-antimatter asymmetry through phase-driven CP violation, and remains consistent with Planck CMB parameters (n_s~0.96, r < 0.01), DESI BAO constraints, JWST ultra-faint dwarf observations, and precision flavor data. Quantum corrections via vibrino loops preserve unitarity, while UV completeness is achieved through asymptotic safety fixed-point RG flows. The theory is highly falsifiable with near-term observations: amplified gravitational-wave echo trains and sidebands detectable via LISA event stacking (delay Delta_t ~ 10^{20} to 10^{-18} s), hybrid DM core profiles and subhalo counts with JWST/LSST, chiral low-ell B-mode bumps with CMB-S4 and ~10 TeV resonances at FCC. Laboratory analogs using phonon resonators and Bose-Einstein condensates enable tabletop tests of emergent forces and frequency interference. This preprint presents the full theoretical framework, including detailed mathematical derivations, toy-model calculations, and parameter constraints. Version notes: minor formatting improvements, and file compression in v2. Keywords: unified theory, emergent gravity, fuzzy dark matter, ultralight scalar field, gravitational wave echos, cosmology, Standard Model embedding.