ok, here is what would be cute and girlie I have other ideas but this is the most girlie one lol.
White leggins a white tutu (which I could prob buy but is also super easy to make on with new sewing involved, let me know if you need help with that) and a white turtleneck with a red robin for the collar. Then get a white baseball hat, but black eyes on it with paint or fabric. Add ears with 2 pieces of felt or fabric and then put a tiny punkin on the tip of the hat brim for his nose (you should find one in the like fake flower area of a craft store or even walmart, ya know the things you can use to make door hanging and stuff.
I think it sounds easy, cute and girlie. If I didn't already have an idea I might do it lol.
I have 2 other very different ideas but like I said this one is the most girlie and I think the easiest to put together.