[coolman50544]

[...] the effective nuclear charge increase from the loss of two electrons is more drastic for 3d orbitals than the 4s orbital [...]

Why? 4s orbitals are lower than 3d. They should be more sensitive to additional protons.

Consider the difference in radius between 3d and 4s electrons. Potential energy decreases as radius between charges decreases.

[Enthalpy]

[...] a sum of +z and -z from the upper right z² would have only two lobes in the xy plane [...]

Porca miseria! The upper right z² at the linked site has zero angular momentum around z. No such thing as +z and -z.
This doesn't change the deductions.