I can't disable find a phone on my iphone 5
When you are not able to remove the iPhone from Find my Iphone in iCloud, try turning on the device and then try to disable Find My iPhone with a mac or pc.

When you erase the iPhone via iCloud, all your settings will be deleted. To place all your data on a new iPhone, you need an iCloud backup or iTunes Backup.

Contacts, photo's, mail, ... Are synced to iCloud by default when logged in on an iDevice. Logging in to iCloud on a new device will fetch all data from iCloud and place it in your photo's, mail, agenda, contacts, ...