"Emotional, lively, expressive" does not describe histrionic; histrionic is a disabling personality disorder related to "attention seeking".

It sounds like you want someone "calm" so I would look for someone you see calmness in. You are the one doing the labeling so the other person is going to "appear" to be like you have decided they are so they're going to appear to act that way to you too. It's like anything you "look for" you see more of it (pick a color for a car next time you're driving somewhere and you'll see that color car everywhere :-)

If you don't want to put the label before the person, try learning about a person from experience with that individual instead of from what you read!