My icloud and itunes have 2 different email addresses
I can’t use “Find my Phone”. I can’t find my cellphone.
iPad, iOS 12
There is no problem using a different email addresses for those. In fact you can use a different one for Face Time and a different one for iMessage. The issue you are having is not that you have 2 different addresses. That being said you need to keep track of two different Apple IDs passwords, questions or 2 Factor Authentication.
If you need to reset a password i’d Follow this article.
I hope that helps.