For the record and future search ability, I did confirm with Undercover Tourist that I can link to MDE and retain the refund-ability of the tickets! Exact language is here:
Kelsey (Undercover Tourist)
Jun 4, 2020, 10:28:39 AM EDT
Hello,
Thank you for reaching out to us! Yes, you can link your tickets to your Disney account, as this will not void the return policy.
However, your tickets will never lose their value. If your tickets do become non refundable, you can use them towards a new date in the future.
Thank you for making us part of your vacation,
Kelsey
Customer Service
Undercover Tourist