Re: phone calls showing on all iphone 5 with shared cloud
That's how it works. The key is the "sharing a cloud" account. Use separate iCloud account for contacts. IMO, this is a flaw in Apple's design... there needs to be a way to share Contacts across multiple users/devices without this issue.
Originally Posted by iMore Question
Another downside to sharing contacts is the My Info issue. Go to Settings > Mail, Contacts, Calendars and scroll down to the My Info section. The name there will be the same on all devices who share the Contacts via the iCloud account.