The grain bill sounds ok to me. When you say "steep" for the last hop addition are you planning to dry hop or put in at flameout? I would probably skip that part since the hop aroma might trump any coconut aroma. Also, 1lb of coconut probably would be barely detectable. Coconut isn't a very strong flavor in and of itself and I've personally found when using fruit several pounds are often needed for a discernible taste contribution. But, I've never used coconut yet so for all I know it could be an exception, I doubt it though.
Oh, and for the yeast why not use an american wheat yeast or an american ale yeast?
*EDIT - also just realized that grain bill is a bit light at only 6 lbs. I would probably up it to 8-9lbs myself. But that is all preference really.