Khan Academy and Clever integration for our school district

The reason behind the question below - our students (K-8 School District) between K grade and second grade don't have emails, and most of our students' emails are not active for correspondence, but rather for Google Classrooms usage.

According to the article below from the Khan Academy and Clever integration, all students in the district should have email accounts in order to link their Clever account with Khan Academy or to login with their current Gmail account if they at 13 years old or older the link is below:

https://support.khanacademy.org/hc/en-us/articles/360043558811-How-do-my-students-get-started-with-Khan-Academy-through-the-Clever-Library-

Could someone please verify if it should be real active emails within our district, or it can be inactive emails that are used only for Google Classrooms (it's true for the most of our student emails in the school district) or could it even be inactive futuristic (made-up) emails that would be assigned to the students in the future when they move to the third grade?

Thanks a lot for any information who works with Clever and Khan Academy.

Respectfully,
Sergey Malygin