Olive is too Popeye for me, though you could wake me at midnight for a dish of black olives, and I love the Olivia character in Twelfth Night, so my choice is easy. But I wouldn't use either. There's an Olive in my family tree, nice person, but not nice name, and like you I find Olivia too decorated.But, it would go better with Rosemary than Olive would. Er ... maybe some other plant might be more convenient?