Does Santa have a wrapping paper different from the rest?
No, Santa has it easy-no wrap! Everything is assembled and ready for play. That way, on xmas morning the kids have something that they don't need to wait for.
Does he have printed cards for the children?
Cards? no, no, Santa has it easy. . . no cards.
Does he visit the children while they sleep?
He comes when they are asleep.
Where are the stockings?
In the family room over the fireplace.
Does he eat what is left out for him?
Of course! Maybe not all of it and sometimes a cookie has a bite out of it. We usually leave a treat (cookie or candy) and some carrots. Recently, the kids discovered "reindeer food" and so we usually sprinkle some oatmeal outside for the reindeer too.
Does he leave a calling card, other than the presents?
No, although if the fireplace was a regular mason fireplace rather than a gas one, we might do as my parents did and leave a boot print in the soot.
Does he visit Grandma and Grandpa's house and have ask them to bring presents to your children? Does the paper and card match?
My parents fill a stocking for the girls. But the girls know that this is from grandma and grandpa. For that matter, I still get a stocking there too.

But, again, this part of xmas doesn't get wrapped.
I LOVE this part of the holiday. It is so fun. My oldest two know about Santa now, but it is still fun. Kinda secret Christmas spirit spy. I wish my second would have held out for one more year, but oh well. . . she is in first grade but is one of the older kids (her b-day missed the cutoff). They are very good at keeping it alive for my little one. For us, Santa is the personification of the Christmas spirit.
Amy