I don't like
Noah for a girl. Theoretically it works because it has quite a feminine sound, but
Noah is SO common for boys that a girl called
Noah is just asking for trouble.
Noa is marginally better, but looks like a trendy spelling of
Noah and sounds the same, so I still think people would assume it's a boy.
Irene is the first name I thought of when I saw
Reenie. I don't really like it, though,
Reenie sounds whiny!