First-principles calculations of spin transmission and perpendicular magnetic anisotropy in artificially stacked Fe(110)/hBN/metal heterostructures have been employed to study the dynamical response of tunnel junctions to applied axial fields. By projecting the effective electric-field gradient densities and magnetic shielding constants across constitutive atomic layers in the scatter region of the device, an unusual site-dependent spin response is unraveled at the Fe/hBN and hBN/metal heterobilayer interfaces. Analysis of the Fermi-level topology reveals an exotic electronic phase characterized by electric-field induced spin flip relative to the ferromagnetic ground state. The calculations reveal unique signatures in the spin transport phase and dynamical effects are observed as field tunable perpendicular magnetic anisotropy. In particular, magnetization alignment preferences are observed in the spin transmission, electric-field gradient localization, and a vanishing magnetic shielding at finite electric fields. Results show that V-capped stacks have a relatively superior perpendicular magnetic anisotropy suggesting that the atomic species of the free layer plays a dominant role in spin-based information storage using Fe(110)/hBN/M stacks.