The polarized infrared reflectance and Raman spectra of the three quasi-two-dimensional -(BEDT-TTF)(4)[(H3O)Fe(C2O4)(3)]Y bifunctional charge-transfer salts, where BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene and Y=C6H5Br, (C6H5CN)(0.17)(C6H5Br)(0.83), (C6H5CN)(0.4)(C6H5F)(0.6), have been measured as a function of the temperature. Signatures of charge inhomogenity have been found in both Raman and infrared spectra of the -(BEDT-TTF)(4)[(H3O)Fe(C2O4)(3)]Y superconductors. A 100 K transition to a mixed insulating/metallic state is clearly seen for the first time in the temperature dependence of the electronic spectra of superconducting -(BEDT-TTF)(4)[(H3O)Fe(C2O4)(3)]C6H5Br. We suggest that this phase transition is due to subtle changes in the ethylene groups ordering, which are related to a structural phase transition in the anionic layer. The infrared and Raman spectra of quasi-two-dimensional metal -pseudo--(BEDT-TTF)(4)[(H3O)Fe(C2O4)(3)]C6H4Br2 are also investigated.