From what I understand, I believe the long-term intent is for data fusions to inherit their pdp policies from parent datasets (we have one dataset that determines all pdp policies). I'm told some time between now and the user conference this should be up and running. We've enjoyed data fusion for simple joins as it runs…

Are you using publication groups or PDP to limit/distribute content? We had the same issue when we used Publication Groups to distribute. Since moving to PDP Favorites, Alerts etc. are available to all users.

There are a number of apps that will calculate expected results, I don't know of any native functionality that does that at this time.