She sure is adorable and I'm glad that you've become a foster failure. Out of the names on your list I also likes Maia the best. Here's a link to many other feminine greek names Feminine Greek Names.

If you want her name to start with an "M" then these are my other favorites:

Melaina-meaning black,dark. This would fit since she has a lot of black fur.
Melantha-dark flower. Since she's has a lot of black fur.
Melina-derived from meli meaning honey. Since she's so sweet.
Melitta or Melita- meaning honey bee. Since she's a sweetheart.