  Iron-substitution in hexagonal YMnO3 causes isostructural intra-lattice
changes exceeding those of the lattice cell, contrary to the effects of
non-magnetic B-site dopants. Magnetization M(T) evidence antiferromagnetic
(AFM) ordering of the specimens with little weak ferromagnetism, and the
metrices of exchange interaction suppress with Fe-doping, attributed to the
lengthening of the Mn-O planar bond lengths. Ferroelectric (FE) P-E hysteresis
loops reflect subdued and conductive ferroelectricity with increased
Fe-substitution, traced to the reduced polyhedral buckling. Dielectric
{\epsilon}'(T) results showing highly doping-dependent anomaly at the N\'eel
temperature signify strong magnetostrictive tunability and imply linear
magneto-electric (ME) coupling. We recognize a correspondence of the
structure-property changes versus Fe-doping, with the reported magnetostrictive
effects upon cooling below TN. Correlations of AFM-FE-ME properties with their
relevant microstructural attributes underline the spin-lattice-dipole coupling
and provide significant characteristic figures.
