This video includes the experiment with a larger ball and a smaller ball (the smaller ball clearly rebounds).The Newton's cradle is not the earth or a solid lump but is made out of separate parts which can be put into contact with each other. I think the experimental results speak for themselves. If you haven't already done so look at the you tube videos on the cradle. There is no noticeable rebound.
You can also see in slow motion that clearly more that one ball moves in the normal experiment.