We prepare PDF forms in Acrobat and then generate prefilled forms using pdftk. The issues we run into is that even though we prefill checkboxes with check marks, the check marks do not show up in Acrobat or Reader but we are able to see them in all other browser pdf viewers. You have to click on the checkbox before the checkmarks show up and they disappear after you click away.
We tried to embed Adobe Pi (otf) and Zapfdingbat (ttf) using Print --> Properties --> Default Settings --> Edit... -- both fonts were downloaded from the internet but it still does not work. Seems to be that when we check the Document Properties, Zapfdinbat (otf) in OpenType font is still missing.