You can't use FileMaker to generate a PDF form that can then be edited via Acrobat Reader, but you can pop up a FileMaker form to be filled out and then use it to generate your PDF file--which produces much the same results.
You can export data in excel format so that should also be possible for you to do.
Do you think the App or the web server (instant web publishing) would be the better solution for what I'm trying to accomplish?
IWP has limitations that you'd have to respect in order to get it to work. FileMaker Go will be closer to a typical FileMaker Client type interface for them to use.