Re: names on my mind - wdyt?
Hallie: Love it, although I might get a different vibe from it than you do. I think it goes less with Calla and more with names like Iris, Rose, Evie, and Esther.
Mara: Very pretty. It's a warm, quiet name.
Maren: I prefer Mara, but I like Maren too.
Merit: Eh. I echo mirfak's Meret suggestion. It doesn't immediately bring merit badges to my mind.
Birch: I picture a birch rod for corporeal punishment, so pass.