A model for thermal fluctuations on surfactant-laden liquid-liquid crystal interfaces is formulated and used to derive the expression of the mean square displacement as a function of four elastic moduli of the interface. The measurable liquid crystal contributions to thermal roughness include the average molecular orientation, the interfacial anchoring modulus. and the bulk elasticity modulus. Surfactant-driven interfacial orientation transitions provide an additional means to extract interfacial elastic moduli parameters in surfactant-laden liquid-liquid crystal interfaces in conjunction with thermal roughness measurements.