You just literally paid 600£ for a phone, where you are not even aware of it's capabilities.
Yes you have to and also deactivate iCloud & Find my iPhone.
As long as you use iCloud, yes it will be transferred automatically.
You can also make a backup to iCloud and restore it straight back to the new iPhone with Wi-Fi.
To get keychain transferred along with your credit info, you'll be prompted for a password you gave and/or a text message confirmation.
its total 720 24 months..no 4G yet in my area fromO2....prob years before nfc is used in u.k. (if at all), the activate de activate iCloud and find my phone..is that via the 5 and once I put the sim in the 6 how do I then 'wipe' the 5 (If I need to)