Solution design for dynamic generation of editable email template

I have a requirement where I have a wizard form with 2 steps. In first step, I need to fill in some mandatory data fields and when I click on next to move to 2nd step, then on the basis of the data filled in for those mandatory fields in step 1, a dynamic email template is generated which user can freely edit. 

The problem I'm facing here is because generated dynamic email template is displayed in an editable paragraph field and formed on the basis of data in mandatory fields. Now, user can also edit the words that came directly from mandatory fields in the email body or subject. This can cause data inconsistency issues, data which is saved for mandatory fields in DB and data sent in email.

What can be best solution for this problem from UI design perspective - I thought of validations but it seems next to impossible to validate the data entered in free paragraph field with what is entered in previous step and then I thought of making the mandatory fields data as readonly in next second step, but this misaligns the whole form itself and doesn't look good from aesthetics perspective.

Any help is appreciated from solution design perspective.

Thanks in advance