I am not sure if i get this right, but have you tried to simply insert a GDPR Consent Checkbox for the list? Basically you go to your email list, click the custom fields counter and from there you can add your custom fields to the list.Ok, but where is the configuration which let the insertion of the 3 default fields (EMAIL, FNAME and LNAME) in a new list?
Wise!Our GDPR advisor told us to impose the "consent" field to our customers so they must get the consent from their subscribers (or fill it by themselves) for the new lists.