LEED v4.0 Energy Model: How to Handle Unknown (Central Plant) Equipment Data for Tenant Fit-Out?

I’m working as an energy modeler on a 3‑floor office fit‑out within a 42‑story building in New York City (LEED v4.0). The base building central plant (AHUs, chillers, cooling towers, etc.) serves our project, but we currently have no access to owner equipment data such as capacities, efficiencies, or control sequences. This makes our proposed model potentially indefensible. We’ve been advised to consider three paths: (1) treat chilled/hot water as purchased energy using DES enthalpy with fictitious rates; (2) model the full central plant using LEED default efficiencies; or (3) obtain owner data and prorate to our scope (currently not feasible). My question is: How should we properly implement Option 1 or Option 2 in compliance with LEED guidance? Specifically, what assumptions are acceptable for purchased energy rates, pumping/distribution losses, and default efficiencies/curves for chillers, towers, boilers, and AHUs when actual data are unavailable? Any examples or best practices that have passed LEED review would be greatly appreciated.