IOS – How to change the photo used for iOS8 Family Sharing

No. Each family member would have to use purchases in the cloud to download your entire music library.

I know of several people that tried family sharing and I've gone back to one Apple ID because of how well iTunes match works for them. Losing that feature to gain the rest wasn't worth it in the short run.

My gut feeling is that sharing between two adults it's better to stick with one Apple ID and families with small children will prefer a family sharing in the 8.0 incarnation of the feature

"Up to six people in your family can share purchases from iTunes, iBooks, and the App Store without sharing accounts. Pay for family purchases with the same credit card and approve kids’ spending right from a parent’s device. Easily share photos, a family calendar, and more to help keep everyone connected."

https://www.apple.com/ios/whats-new/family-sharing/

In-App purchases are not supported by Family Sharing.

http://9to5mac.com/2014/09/19/ios-8-how-to-set-up-and-use-family-sharing/

If a free app has been shared and a user makes in-app purchases, this is supported; however, if the user leaves the group in which the app was originally shared, the user will need to purchase the app on their own and then restore their purchases.