I helped once to publish the proceedings of a smaller conference using LaTeX.
This was done by creating PDFs from each article, without headers and footers, especially no page numbers. The PDFs where then included in a main document using the pdfpages package. You can add a header and footer over these pages to superimpose a running page number with the pagecommand option. We also added some code to have PDF bookmarks and a table of contents. You can also use indexing etc.
There was a small database with the information about each article, like author, title and PDF filename.
Basically we had an input file (DB) like this:
\journalarticle{Author}{Title}{Other info}{PDF filename}
\journalarticle{Other author}{Next title}{..}{PDF filename}
% ...
Where \journalarticle is a custom define macro which includes \includepdf and the bookmark, ToC and index macros. I don't have the exact code available any longer. If you have a real DB you should be able to produce such a TeX file using a script.
I can recommend such an approach over combining the sources of the article, which can cause a lot of issues if the sources come from different people, even if a common template and class was used. You should definitely provide a document class and a example document template to the authors. Also, state all technical requirements, like no page numbers, very clearly.