A: is it possible to insert a paywall in a PDF that appears after a certain page and prevents the person from continuing reading until payment is made - Yes but depends on payment gateway. With little bit of scripting, we can achieve it. I would be happy to help.
Is it possible to insert a pop in a PDF that appears after a certain page and prevents the person from continuing reading until they provide email? Yes. Already available through our configuration.
Is it possible to use EnsoView to prevent PDFs from being downloaded or printed? Yes, it is a simple Toggle configuration which you can enable to disable.
I can embed dynamic elements in the PDF file, such as variables, texts, watermarks, etc - Yes, Form filling, Watermarks are supported. But we do not support Digital signing as of now.

Do let me know if you have any further questions.