I concur! At least I like it better than ShadowStrike.Eerie Rush has a certain ring to it.
As for height and weight... I imagine it as being fairly small. Able to sneak in or out of areas fairly easily.
I find Elegy's and other 'light' suggestions as good ones. However, personally I imagined this thing as being even tinier. Perhaps around 1 and half to 2'ish feet tall and in the 20-50 pound range.
I really don't think it needs a pre-evo. It screeches non-evolving pokemon to me.