I really like
Lark for a girl. It's spunky and energetic. I've toyed with the idea of Skylark or Meadowlark as a name, but they seem a little too cute.
Lark on its own has more respectability to it.
I would use a more conventional mn with
Lark, though.
Lark and
Annie sound perfect together. They sound like they belong in a field somewhere, gatherine wild flowers. Delightful. (But I only like
Annie as a nn for something else. Wait. "
Annie Linnea" just popped into my head as a sibling for
Lark.)