apple id/ icould family sharing

I was hoping someone could help me or point me in the right direction. I have been using my old mobile me account converted into icloud account for my phone (thankfully paid for by work) on my iPhone 5s and iPad mini. Before family sharing was available, I wanted my wife and 2 children to be able to use the apps/music/movies that I had already purchased, so I set them all up on their phones using my apple id (not my icloud ID). It did create some issues w/ calendar, contact and photo stream sharing as you might imagine, but overall it was fine. Now with family sharing, I would like to give each of them their own icloud account, but use family sharing so we can all use the same app/music. How do I switch them? I have already made sure to do a back up to the cloud, but when I go to settings-->icloud and try to sign out, it warns me that everything on the specific phone that is from the cloud will be deleted from the phone. I don't want them to lose that data. What should I do? Should I back up the info to the computer, instead of the icloud? Last question, is there anyway to have them share my icloud for storage, documents, etc? I am paying for a 200g cloud, it seems that the whole family should be able to use this. Sorry for the long question 🙂