  Employing a first-principles and model Hamiltonian approach, we work out the
electronic properties of polar-polar LaVO$_3$/KTaO$_3$ (LVO/KTO, 001)
heterostrctures, with up to six layers of KTO and five layers of LVO. Our
analyses indicate the existence of multiple Lifshitz transitions (LTs) within
the $t_{2g}$ bands, which can be fine-tuned by adjusting the number of LVO
layers or applying gate voltage. Contrary to the experimental report,
spin-orbit coupling is found to be negligible, originating solely from the Ta
$5d_{xy}$-derived band of KTO, while the 5$d_{xz}$ and 5$d_{yz}$ bands are
considerably away from the Fermi level while LVO overlayers having no role in
it. Magnetic properties of the heterostructures, due to Vanadium ions, exhibit
a pronounced sensitivity to the number of LVO and KTO layers. Our calculations
indicate that the interlayer AFM, (so called A-AFM), is energetically most
favorable. This is further supported by ground state energy calculations on
extended $\sqrt{2}\times\sqrt{2}$ supercells. Moreover, we find that an
insulator to metal transition at the interface requires four LVO layers,
corroborating the experimental observation. The interfaces featuring
ferromagnetic (FM) ground states turn out to be \textit{half-metallic} after
the critical thickness is reached. Considerations of the magnetic interactions
appear crucial for the experimentally observed critical thickness for
metallicity.
