I think it would be kind of silly to use a Japanese name on somebody who has no connection to Japan, at least as a fn. Yes, people use names from other cultures all the time, but you don't see Japanese people in Japan naming their kids Coinnor or Jose or Svetlana.
Your shorter Japanese names would work pretty well as mns. Midori is cute, though it is a melon-flavored liqueur. Steer of Ashitaka, look at the word that's wright in the middle of it.