The material is a green velvet, quilted with a floral pattern to batting. I found barely a yard of it at Mood last month, and bought the whole remnant. Definitely more than enough for warm little vests to wear over their holiday dresses.
Kate's vest is lined in an ivory cotton with some embroidered braid inside (I'll show the inside once it's done). Here it is on her, unhemmed:
I borrowed a trick that Summerset shared a long time ago.. I kept a small scrap of the velvet and used it underneath the vest when I had to press the seams. It helped preserve the pile of the velvet and keep it from crushing under the iron.
And here is that butterfly dress from the dress pattern in 9677: