Oh man, everything I wrote was just deleted. I hate that so much.
Clara- it's a sweet, quiet little name. Very pretty. It sounds lovely with all the girls, but I feel like it's almost too quiet beside your boys' names.
Juliet- if you don't like Julie, I'd pass on it, because people are going to want to call her Julie. You can insist on Juliet until you're blue in the face, and you're going to get those stubborn ones that won't budge, or Juliet herself may want to be a Julie.
Freya- this is one of my most adored names, and one I can't use. Freya is one of the greatest names. Feminine, powerful, the imagery is just gorgeous... I love it! I do agree that it seems to overpower Alice, Lucy and Evie. It sounds great with Ophelia and all the boys though!
Elowen- this one is practical magic. It's dripping in magic, but the sounds feel comfortable and practical, because they're used in other more common names. I can understand not falling for a name, as perfect as it seems, but from the outside looking in, this just feels like the most perfect name for you.
Loving dantea's suggestions, especially Isadora, Thalia, Phaedra, Avalon and Calypso. Evadne, Evanthe and Genevieve are three of my favorite "Evie" names, as is Everild, though that may be too much magic and not enough practical.
I think some of the names in my signature might suit the "practical magic" criteria. I don't remember what all is in there, so I may suggest some that are listed there already. Sorry. :)
Most of those aren't practical, are they? Sorry!
Siobhan / Chevonne
edit: and a bunch of other great suggestions just popped up while I typed this, twice. :D Sigh!
Clara and Clarabelle are totally different. Anyway, it's the -belle part that makes Clarabelle a cow name IMO, not Clara.
I have never heard Juliet shortened to Julie. I don't think that's a concern.
Freya sounds fine with all of those names.
I don't see Elowen V___ nn Evie working out. Honestly, I think Evie works fine as a stand-alone name anyway.