The original patterns were written for 4 ply but, as the elves I have been knitting for are a little larger than the Little Cotton Rabbits, I have made mine in baby soft double knit and alpaka double knit.
Suzymarie has called this design 'Santa's Helper Dress', the instructions are available on Ravelry. It includes instructions for converting Julie Williams cloak into a Christmas cloak to match the dress.
I made similar changes to Julie Williams sweater pattern to get my Santa jumper with the belt and buckle.
On the back view of the jumper you can just make out the little button fastening.
I hope you have enjoyed seeing all of these Christmas outfits as much as I have enjoyed sharing them with you.
Happy Christmas in July, enjoy what is left of it.