Sheltered life wrote:
two-step identification apparently makes it impossible to log in to iCloud without your trusted device to hand.
Not correct. If you have set a trusted phone number, which should not be the same number as your own iPhone, you can get 2 Factor Authentication codes sent to that number. The number can be a land line or even an android device that can receive SMS messages.
So, it it possible to take a spare iPhone synched to your Apple ID which would carry exactly the same data - even if you manage to wipe the lost phone?
Sure. You can have up to 10 devices logged in to your Apple ID, and trust from those as many as you want to get 2 factor authentication codes. You can have a secondary phone, an iPad a Mac, an iPod touch, Apple Watch as trusted devices to get 2 Factor Authentication codes.
click here ➜ Two-factor authentication for Apple ID - Apple Support
What is a trusted device?
A trusted device is an iPhone, iPad, iPod touch, Apple Watch, or Mac that you've already signed in to using two-factor authentication. It's a device that we know is yours and that can be used to verify your identity by displaying a verification code from Apple when you sign in on a different device or browser.
Learn how to see and manage your trusted devices
Do note, passes, tickets stored in Wallet can only be accessed from an iPhone. You should always have a backup option to retrieve tickets and passes, such as form the issuer's App on another device or a confirmation email sent by the issuer.