Ahh I would say Veronica is definetly extremly evil. Her evil is just very different from the most of the cast. She seems very often completly indifferent to the suffering of others, but also enjoys and abuses a lot of the powers she has. She is also very high on experimenting on humans. When she sponsors Kane in the beginning she tells him that she is basically in between high morals and sadistic cruelty and don't like either of them. It seems like she can't even understand how cruel her experiments are. While her sisters are all sadistic devils, she is a cold hearted monster.I'm gonna have to disagree on that one. As I saw the lore, Alexander felt his heir needed to have the perfect bloodline: Alexander's and Callista's (the perfect woman). Because of his infidelity they never had children so their children (Kane and one of the Karlsson sisters) would need to sire the chosen son. I never saw where ethos had anything to do with it; just passing the trials that Alexander had to endure at the hands of his own sisters.
I see Veronica as being purely pragmatic (neither good nor bad even though I do see her enjoying some evil things); the reason Alexander chose her to manage the gambit was because he trusted her to be impartial in executing it; she won't try to sway the results.
About Alexander, it is told to us that he became much worse after Callista and his sisters left. I interpret this as he just didn't gave a fuck anymore, because he lost the three people that actually mattered to him, so he just doubled down on being awful. But maybe, just maybe deep inside he hoped that with the influence of Callista their could be someone in his family who could be the man that he wanted to be, but failed to be himself. This would also explain why he is so high on Olivia - if she is the daughter from the intro - as she was raised by Callista.