I feel like Olivia and Charles would probably hate each other, mostly because of Olivia. Barbara always hated Bruce and his kids (except Tim), which would probably give Olivia a bias against them, plus because of her negative experiences with Tim, she'd likely be even more against his family line specifically. Charles always thought Tim was a great father, and I could see Olivia making a sarcastic comment about him that would spiral into further tension. Charles wouldn't know why Olivia's not fond of him or Tim, but would probably assume she's just being a jerk. Barbara has no ill will towards Bernard, so it's likely Charles and Olivia would have the opportunity to interact more than once. Also Charles would probably like hanging out at Barbara's place, since Bernard wouldn't be very good company.