The resonant layer effect (RLE) is investigated for a multilayer structure with iron nanoinclusions. The RLE tuning and strength are analyzed as a function of nanoinclusion filling factor and resonant, cladding and guiding layers thicknesses. Crossing, splitting, and quasidegeneration of modes in the structure dispersion diagram are discussed, along with its relation to the RL effect detuning and structure-coupling regime. For the range of parameters considered, multiple resonances are tunable in the multilayer structure. Optimized RLE TE and TM polarizers are proposed for operation at 1550 nm based on modal loss and field confinement calculations. For the TE-pass polarizer, a 201.1-dB rejection ratio and insertion loss are obtained, while for the TM-pass polarizer, a 95.6-dB rejection ratio and insertion loss are achieved.