Pete,
Great question and you've just describe three of our products that all work together and are tied into the platform overall.
Via SharePoint 2013, you can use what we call "Nintex Live Forms" which will allow anonymous access to the form to submit. This is for submissions purposes and will allow you to capture their name, email and whatever else you want to capture within the form. The form is accessed via a url which can be bookmarked on the iPads.
When the user fills out the form, the data is then pushed to SharePoint where its stored. A workflow can then be setup to run on "new item" which can then send them an email. Instead of just sending an email, you also mentioned sending them a PDF. You can use document generation action to generate a specific document based on MS Word formatting that can also push user specific content into the PDF. This PDF can then be sent to the user so its tailored to them specifically and what they entered into the form. (Personalization always helps)
Eric