My personal suggestion would be to name her Artemis, after the Greek Goddess of the hunt and the Amazons, but then I am rather fond of the Greek myths (and you must admit that Hermes is a far superior name to Scabbers).
Your niece would like to offer up Seeker, as your new kitten sounds like it is chasing after a snitch, and Lucy is also now asking to visit next weekend to play with the kitten because I told her that no we are not getting one for here (it would give poor Hermes a heart attack).