Friendship cake is one of its kind as there are not much dishes that take so long to make. And yes you would need approximately 1/4 ounces of active dry yeast for the starter. On the 30th day you will have to drain juice from fruit and the juice can be divided into 4-5 jars that you can distribute amongst friends who can make Friendship cakes for themselves. Here is a link that will give you a complete recipe for Friendship cake along with starters.
www.cooksrecipes.com
www.cooksrecipes.com