Whatever, because it is to be a charity quilt and simple is your goal, I'd leave off the pinwheels--I don't consider anything "HST" as "easy" and quick.
Any other other suggestions sound good to me. Some kid will love it. DO you have other brights you can add. Don't worry about it being "too bright" for someone. I've never had that happen. But I've have had it to be "too light".