iCloud PhotoStream syncing to seperate Windows devices with shared App/Music/iTunes sync
Simple.


Use one AppleID for purchasing.
Use one or many computers to download this content. Remember that iTunes can sync apps to computer A and music to computer B and photos to computer C. Each person can decide to join the communal computer for App syncing / backup / downloading without it affecting their Photo browsing.
If they each get an iCloud account and use it for the rest - they can use the iCloud software on their PC to get the pictures or sync manually like any other photo device connected via USB.


I haven't tested it, but WiFI sync might also be available on the PC side of iTunes. Good Luck! Let us know how you fare...