I have, sort of, been following this. All I can say, is that I have no trouble printing PDFs, using QPDFView (I scrapped Lucide when QPDFView became available).
From the first post:
Warpin gives an error 'Invalid package index "5"
This is something that is wrong in the WarpIn installer. However, it can be worked around, by installing all of the other WarpIn packages first, then install the cups-base-1_4_8_3.wpi package. There seems to be something in the full WarpIn package, that has fixed the PDF problem (probably pdftops), that is not in the ZIP files.