Unconstrained higher spins of mixed symmetry II. Fermi fields

110 pages, LaTeX. Thanks to the referee for urging us to extend Section 4 and to add Section 3.4.1. Final version to appear in Nucl. Phys. BInternational audienceThis paper is a sequel of [A. Campoleoni, D. Francia, J. Mourad, A. Sagnotti, Nucl. Phys. B 815 (2009) 289, arXiv:0810.4350 [hep-th]], and is also devoted to the local "metric-like" unconstrained Lagrangians and field equations for higher-spin fields of mixed symmetry in flat space. Here we complete the previous constrained on-shell formulation of Labastida for Fermi fields, deriving the corresponding constrained Lagrangians both via the Bianchi identities and via the requirement of self-adjointness. We also describe two types of unconstrained Lagrangian formulations: a "minimal" one, containing higher derivatives of the compensator fields, and another non-minimal one, containing only one-derivative terms. We identify classes of these systems that are invariant under Weyl-like symmetry transformations