Easter Blue M's?

Easter M&Ms come in such pretty colors that when we got some last year, we were excited to experiment with them.  Sadly, the M&M colors were too faint for good chromatography--we could hardly see the colors on the paper, much less any separation.  So this year, we decided to concentrate on the m's themselves.

First of all, are these m's made of the same stuff as normal white m's?  Experimentation shows at least one difference: these m's seem to dissolve.

Blue streaks sinking down from the bottom of the m--dissolved blue dye?

That led us to the big question: do the blue m's float?  What about all those little bunnies and sheep?  Apparently so.

What about the speckles on the M&M eggs?

Yes, they float too.

Which leads me to my final question: how do they print the speckles on all sides of an oblong egg?  Alas, experimentation can't answer that one.