Forms 2.0: Looking for Advice on a Progressive Profiling Challenge

Here's an outline of what we're trying to accomplish:

We currently ask for First Name, Last Name, Email, Phone Number, Job Function, Department, and receive the rest of the company information through ReachForce.  We would like to display one or two questions if this information has been obtained on their lead record.  Ex: If the above fields are not empty on the lead record, don't display any of them, and display one additional question such as "Current LMS Provider?". 

The challenge around progressive profiling we're running into is that there doesn't appear to be a way to only display one field on the form on the 2nd form fill out (Meaning we captured all six fields on the first fill out).    The only options appear to have the original six fields be displayed plus the additional progressive profiling field, or set the number of visible progressive profiling fields to six so we capture the needed information on the first fill out, which stops them from appearing on the next visit, but eliminates the ability to display one at a time.

Ideally, we would like to avoid custom Javascript.  The only solution I've thought of is to create custom fields to capture on online forms mirroring the current fields, then set up triggers to map them to the current fields. Ex: New Field "Online First Name" goes on the form with the Label "First Name" and put the actual "First Name" field as a hidden autofill field on the form, and set up a visibility rule to only show "Online First Name" when "First Name" is not empty. 

Any better ideas?

Thank you,

Austin