In theory the following command-line parameter should produce PDFs pop the print dialog automatically up:
-param pd4ml.print.dialog.popup true
Please give a try.
I am not sure if I understood your second question correctly, as “PDF tag” can mean different things.
So you would like to autoprint some sections of generated PDF documents? I do not know what you are going to use on the sever side as a print application, but if it should be “standard” Acroread, I would to take a look to the attached document. Acroread command-line parameters allow to jump to a particular section of a PDF document (marked as a named destination).
By the link you may find Acroread command line options for silent printing:
Probably by combining the named destination jump and the silent print command you’ll achieve the needed functionality.