Thanks Jeff. I've tried numerous options but can't figure it out for my use case.
I have tried the ALWAYS show email address checkbox option w 2 Blank fields as shown below. That works like a charm for showing Email, First, Last on the first visit. On return visits, only the email address is shown
What's the issue? We've found that people return and sometimes change their email address or passes a cookied link to someone else who enters a new email that always shows. In this case, a new lead is created without First, Last and that lead ends up getting rejected by SF because there is no First or Last name. We always want form submission leads to pass over.