One iCloud account for multiple users
Yes. From Apple's perspective, one Apple ID = one person. If you want to share that Apple ID, it also means that all those sharing that Apple ID will have access to all the same things (purchases, texts, emails, etc.)

You may want to look into iCloud's Family Sharing, which allows up to six Apple IDs to be designated as belonging to one family. That allows the family to  share each other’s iTunes, iBooks, and App Store purchases without needing to share an Apple ID.