"Wait, that didn't work right" - the Dysfunctional Rules Collection

[Wookie-ranger]

I think the Necropolitan with the Human Heritage feat or whatever would heal from both. Not sure I have that right, though.

Nerco + Human Heritage does not give you both healing options.
With the same line of argument you can say that they get harmed by both. Therefore a Neropolitan with Human heritage would be neither healed nor damaged by both energy types.