Low-Energy Phenomenology Closure of the Preferred SO(10)-Compatible QDL Completion

This record is Paper #2 in the QDL–SO10–1 benchmark sequence. It develops the low-energy phenomenology closure of the fixed SO(10)-compatible QDL benchmark introduced in Paper #1. The paper extracts the benchmark’s indirect low-energy signatures: Standard-Model-like visible physics, high-scale singlet-neutrino remnant structure, small neutrinoless-double-beta benchmark, baryogenesis-facing compatibility, proton-decay exposure, collider null expectations, and explicit support/falsification criteria. It is a consequence and traceability paper, not a new ultraviolet benchmark or a complete global scan. All low-energy claims are traced to the fixed QDL–SO10–1 benchmark defined in Paper #1: Bourassa, J. D. (2026).…