For some reason, when I hear the name, "Olive," I picture an old woman. Silly maybe but that's the first thing that comes to mind! I do like the NN "Liv" though.
I like Mallory. It is a nice that, I think, would age well. Suits a child or an adult.
My great grandma was Olive so it makes me think of her. Although she was an amazing woman who lived to be 97 yrs old, I will always relate the name to an old grandma. My sister was due with her first on Olive's brithday so she used the name Olivia. Very popular now but this was 9 yrs ago, not quite as popular then.
