To make it go slower, change the amount of time it takes to do the tween. Change 1 to 7, for instance. I must have somehow mis-calculated the final coordinate somehow. Try just adding fudge factors to stage.stageHeight until you fine-tune it.

To get Jesus to be in front of the starfield, either add him to the display after the starfield (you can re-add him even if he's already on), or add the starfield to a container which is behind him to begin with.