Pass only One Field in URL Parameters to Thank You Page


I am prohibited both by the policy in Google Analytics and by our own GDPR policy to pass the complete set of URL parameters from the main landing page to the formstep2 thank you page. I would like to capture just the first name from the formstep1 main LP. I am already using the progressive profiling script to pre-populate the first set of form fields to the next form step. Question, is there a way to populate a first name onto this second page using DKI but without grabbing it from the URL parameters? I can perhaps come up with a script but then need to have a means to actually pass that first name value to the page itself via DKI.