We investigate an imbalanced mixture composed of two-color fermions and scalar bosons in the hard-core limit, considering repulsive and attractive interspecies and intraspecies interactions. The interplay between commensurability, repulsive interactions, and imbalance generates three insulating phases: a mixed Mott state and two spin-selective insulators characterized by the commensurability relations ${\ensuremath{\rho}}_{B}+{\ensuremath{\rho}}_{F}^{\ensuremath{\uparrow},(\ensuremath{\downarrow})}=1$. For an attractive coupling between fermions and bosons, we found the relations ${\ensuremath{\rho}}_{B}\ensuremath{-}{\ensuremath{\rho}}_{F}^{\ensuremath{\uparrow},(\ensuremath{\downarrow})}=0$ for the spin-selective insulators. State-of-the-art cold-atom setups constitute ideal platforms to implement these unveiled insulating states and verify their commensurability relations.