Advice on my save the date cards!

I really want to incorporate our dog, Sophie into some aspect of our wedding. Since the actual wedding is going to be formal, there doesn't seem to be many opportunities. So I figured the save the date card might be one feasible way!

What do you guys think? I have tried to come up with a saying, but unfortunately, the card will only hold a couple of lines of writing. I would love a short rhyme or poem, but I can't think of any. Any advice would be appreciated.

Also, should STD cards have our last names. There are going to be 200+ guests and I certainly don't know all of them. But can't they figure it out from the return address on the envelope?