iPhone and iCloud security protections

Couple of questions:

1. Can I add a password/passcode to my iCloud account to prevent someone from changing my Apple ID if iPhone is stolen?
2. Can I password protect sensitive apps & applications such as photos, mail, wallet, saved credit cards & passwords in keychain & Safari? Yes, would make these less accessible to me as well but not a big deal compared to my info getting in the wrong hands which can easily happen regardless of how careful you are. — Similar to freezing credit that I recently did due to an account being opened in my name, thankfully I have a credit monitoring service that alerted me of a credit check so I caught it in time)..