Spoon the yogurt evenly into the 12 cups in the muffin pan, then put the pan in the freezer.
Add the fruit into the 12 sandwich bags in whatever combinations you like.
After an hour or two, take the muffin pan out of the freezer and set it on a cookie sheet with a 1/8 inch of hot water. After a couple minutes, you should be able to spoon the yogurt cups out and put one into each of the 12 bags.
Divide the bags into the 2 freezer bags (6 sandwich bags in each), and lay them as flat as possible so they fit into your freezer and take up the least amount of space.