For 2-6 years of age a busy mothers party would be great. There would be invitations shaped as bottles saying to bring your favorite doll. For party decorations there would be little bottle confetti and such.  For activities there would be a day care where the adults of the house "take care" of the dolls, a tea table where they can be served little treats, and final is a dress up station where the mothers can dress up themselves and their babies.  For party favors there could be candy such as "baby bottle" bops and other baby related candies. There could also be a cake that was shaped like a baby that can be made with little candies or with icing so you can be creative. The treat bags can belittle plastic purses with candy lipstick, plastic sunglasses etc..