Is Alestir Black a good name for my character?

I think most literate people would pronounce it the way it should be: i.e., Al-is-tur. I have never heard of Ale-stur, have you? At any rate, I think the name is appropriate because of the ociations with the word "black," the history you provided on the name Alestir, and the fact that one is simple and common, one is not. My only hesitancy would come from the fact that Alestir may be conceived as a little contrived by those who don't know the history. Like naming a y woman character Bambi or Barbi--predictable, you know?