If the "tattoos" were non-permanent (decals or henna) I'd think that was an interesting thing to do...not *my* thing, but interesting.
A permanent tattoo? I would only expect the bride & groom to care enough about the date to make it a part of their body. Maybe their parents....but the parents could prefer temporary over permanent. The guests and wedding party, temporary all the way.
As to Coco Puffs - don't like them, cake is always my preference for a dessert. Although there are a lot more flavors in wedding cakes than I remember seeing at weddings when I was growing up (the plainest of white vanilla cake with white vanilla frosting - usually buttercream)...why the focus on plain white everything? I dunno, no one ever told me *why*, they just served plain white everything = except for the palest pastel mints. No meals - just cake, punch, and mints.