Looks like a very cool InDesign script! I’m sure many could find that handy. Just to clarify your statement, for creating interactive PDFs or to use Adobe Sign in conjunction with the PDFs from InDesign, you can use any Sign account if you are sending the form for someone to Fill and Sign. If you specifically wanted this as a web form for someone to just go to a URL, then you need Business.
Some of the forms your script could be used in conjunction with Adobe Sign. If you have an Acrobat subscription (even via Creative Cloud) give it a try.