Yep, Veronica is capable of being ruthlessly extreme even when she knows it isn't necessary, which implies she secretly enjoys exerting her power to make others suffer even though she pretends she doesn't. Elena comments on it in the very same meeting. There have been enough other small examples of Veronica getting off on the suffering of others to confirm Elena's accusation. All of the Karlsson daughters are messed up in one way or another, save maybe
Even Dominique's uncharacteristic possibly false admission to dom Kane makes me wonder how much of her own remaining ethics she's willing to sacrifice in order to win the Gambit.
Given that Elena didn't even know she had a living daughter until the bombshell was dropped on her, it fits that Olivia wasn't told either. Olivia was probably either an IVF baby produced without Elena's knowledge, or Elena was lied to and told her baby was stillborn when her baby was instead whisked away at birth by Alexander Karlsson and given to Callista to raise. It has been established that Alexander Karlsson in his latter days was a cold-hearted bastard who thought the world of Callista and deeply desired an heir. I can easily see him stealing Elena's child and giving her to Callista to raise thinking Callista would raise a better heir than Elena.
Yep, the story has made it clear that Yvette is Veronica's mother. This is one of at least two mentions I can think of.
No. Callista is not Alexander Karlsson's sister. Alexander Karlsson has/had 2 sisters, Klara and Karin. Klara is the sister of Alexander Karlsson that Olivia is said to look a lot like. It's also been made clear that Alexander deeply desired to produce a child with Callista, but it never happened. So the objective of the Gambit is to