This paper investigates and analyzes an advanced multi-generation combined system that utilizes liquefied natural gas (LNG) as the primary energy source. The proposed system consists of a main Brayton cycle, a supercritical carbon dioxide (sCO₂) cycle, and two organic Rankine cycles (ORCs) as heat recovery subsystems. In addition, a water electrolysis unit for hydrogen production and a reverse osmosis (RO) desalination unit are integrated into the system. By exploiting the energy released from methane combustion in the combustion chamber, the system not only generates 145471 kW of net power, but also performs LNG regasification for injection into the urban natural gas network. Simultaneously, part of the generated power is used to produce 43.1 kg/h of hydrogen in the electrolyzer and to desalinate 30 kg/s of freshwater in the RO unit. A comprehensive energy, exergy, and exergo-economic analysis of the system is carried out using the Engineering Equation Solver (EES) software. The results indicate that the integrated system achieves high energy and exergy efficiencies while simultaneously delivering four valuable outputs, namely electricity, natural gas, hydrogen, and freshwater, at a considerable scale.