I don't know if there's a good way to show which individuals forms were completed, but if you have a separate program for each on-demand webinar, you could always run a program report. You can pick and choose which programs to include in the setup tab, or if you have a separate channel tag for on-demand webinars, you could just choose to include programs with that tag.
The program report will tell you how many members each program has, and how many of them are net new names.