Certainly you would be able to add a PDF to the zip file that you upload to the LMS. But I'm doubtful that would be sufficient. You would need some way to open and present it.
Camtasia does offer a clickable hotspot callout that you might use. One of the options is to link to a file. But the issue with that is that Camtasia will expect the file to be in a location that is reached via HyperText Transfer Protocol (HTTP). The same options are available if you enable the "Display Feedback" option on quiz questions.
So in order for that to work, you would need to copy the PDF to a web location where you can reach it via a fully qualified URL.