PDF solutions?

[Steven D. Arnold]

I'm looking for low- or no-cost solutions to the following PDF
problems.

(1) I need to be able to replace form data in a PDF file with
arbitrary strings.

(2) I need to be able to merge multiple PDF files together.

I have found several commercial solutions; I'm looking for open-source
options.  I have looked at ReportLab and on the surface it doesn't
appear to have ready-to-go functionality in this regard, but maybe I'm
missing something.  Any solution that solves even one of these
problems would be great.

Thanks in advance for any feedback.


steve