1. I like it as a name, but I personally wouldn't use it on a real child because it always makes me think of the Greek goddess (well, personification). Not that it's a bad association - I just have a hard time imaging names I strongly associate with one particular person/character on anyone else.
2. Alrighty...
Nyx AmabelNyx Isra Nyx IseultNyx WrenNyx DeirdreNyx AliceNyx Circe (too themey?)
Nyx ViolaNyx OdileNyx EvangelineNyx ZephyrineNyx BeatriceNyx AnastasiaNyx FionaNyx CiaraNyx FayeNyx ImogenNyx JudithNyx TheodoraNyx PilarNyx Lavinia