Hi Jesse,
You are right that there is no feature in Form Wizard Pro to pre-populate form fields based on the user profile, to do that you would have to implement a custom developed form.
If the user is authenticated when he fills out the form, we do capture the UserGuid in sts_WebFormResponseSet so there is a way to track it back to a specific user after the fact in some cases but it has no mechanism for pre-populating the form at this point.
I've added this as a wish list item in my project tracker so I don't forget about it. I will ponder it but not promising anything on it for now.
Best,
Joe