How about a "Minnie Project Runway?" You could set up the activity as Minnie Mouse needs some new outfits and she's hired a group of aspiring designers - your DD and her friends - to craft them for her. Have a bunch of fabric scraps, lace, ribbons, etc in Minnie's favorite colors (red, yellow, white, black, pink) and some cheap tees that can be cut up and embellished. Fabric markers, glitter glue, safety pins, feathers, glue-on plastic "jewels" - whatever you can find at the fabric, craft or dollar store - will add to the fun. The girls will love to spend time creating the perfect ensemble for Minnie. Then they can each model their creation, or if you have a big Minnie Mouse plush, they can take turns putting them on her, and have a picture made of the "star" with each "designer."
Other ideas - Minnie Manicures. Since you will have several adults in attendance, enlist their help to paint the guests' nails. Of course, one of the main offerings could be bright red with white polka-dots.
- Blindfolded Minnie Mouse portraits. Pair up the girls and have one wear a blindfold. This one is the artist and is given a large sheet of paper and a marker. The other is the guide and must give instructions for the drawing of a picture of Minnie Mouse. "Put your marker down and make a circle. Now pick it up and move over a few inches and make another one..." After awhile, switch artists and guides. This was an activity at DD's youth group a few times and caused lots of giggling and fun. The pictures come out really crazy and for some reason this age loves that.