Re: Wording with PDF file
PDF is an open format and FoxIt is not the only third-party reader, though it is the best one I've used. AFAIK it's perfectly legal, but then again IANAL.
Looking at the docs -- the free version of FoxIt may insert an "evaluation" watermark if you save the document, but you should be fine if you just want to print a modified document. If the document uses special PDF forms, then even the free Adobe Acrobat Reader will let you fill the form in on-screen before printing.