I noticed this question earlier and there was a discussion relating to writing your html report directly to PDF but it isn't recorded as an idea yet.
https://knowledge.safe.com/questions/29382/html-report-to-pdf.html
I am using the HTMLReport generator ALOT since it's release and everyone loves the output but still getting requests to turn this output into a PDF. Would be great if we could do this directly through FME as suggested