Congratulations on getting a new iPhone X, Johnsi776. We want to make sure that being able to move the devices around is as easy as possible. It's good to know that both your phone and your wife's phone is backed up. I want to provide you with an easy way of doing the activation.
Even though you upgraded to the iPhone X on your wife's line, once you receive the device, you can always activate it on your line. It does not have to be activated on her number first. This would be less work for you on your end. You can always activate the device by following the steps on this link https://www.verizonwireless.com/support/knowledge-base-209087/.
When you complete an "Erase All Content and Settings," that will wipe the phone clean (like it's coming out of the box for the first time). Does this help?
KevinR_VZW