I'm not 100% sure, but I suppose you would point all the raw ingredients and any butter/oil etc used to line tins? I'm sure someone with more experience would be able to help better than me but I think this is how I would do it! Alternatively have a little search on the recipe thread and see if anyone has posted a cake recipe there?
Yep, you would weigh and point all your ingredients so you get a point "count" for the entire recipe. Then you can divide it by the number of servings it makes e.g. if you make a cake that is 64 points and cut it into 8 pieces, then it's 8 points per slice.