Do all authors have the right to access LaTeX source code of the PDF manuscript uploaded to a journal's portal by the corresponding author? I am a PhD student about to graduate (finished defense/Viva, pending final thesis corrections and final upload before conferral of degree).

I am a co-author on a manuscript for a journal article. There are 5 other authors on this manuscript. I wrote some chunks of text and created a few figures of the manuscript. 

Our initial manuscript submission to a journal (Elsevier is the publisher) came back after peer review requiring us to do major corrections. The first named author on the manuscript and my two supervisors undertook the majority of this task. For the manuscript writing aspect, I also contributed a revised figure and couple of paragraphs of text for the pending resubmission (I also did other tasks to address peer-review comments such as doing long-running simulations with different parameters etc). 

Right from the beginning, the manuscript was written in LaTeX. I had also written some of the LaTeX code (for a couple of sections of the initial manuscript submission which came back after peer-review requiring major corrections). In fact, the first named author and myself were using git and a shared github private repo for pulling/pushing our TeX source code as we were working on the draft of the manuscript. However, post peer-review, the first named author took upon the manuscript re-writing task for resubmission entirely to themselves, and stopped pulling/pushing TeX code on our shared github repo.

Today, the corresponding author sent me the PDF of the revised manuscript for my comments and approval before resubmission. I requested the LaTeX source code of the revised PDF for my personal archival purposes. However the other authors who worked hard for the re-submission are reluctant to do this. They reasoned to me that a PDF version is sufficient for me to review and offer my comments. My personal thoughts on their behaviour is that they might have strong ownership feelings about the  revised manuscript since the rewriting was quite demanding in effort with large changes/rewrites necessary to address peer-reviewers comments.

My question therefore is: "are all authors on a journal manuscript automatically entitled to see all artefacts submitted by the corresponding author to the journal's portal (such as the LaTeX source code, covering letter and other relevant submission materials)?"
Your collaborator seems unnecessarily protective (or maybe insecure) about the TeX source, and I don't really see what they think they'll gain from it. Hiding some super awesome macros, or ashamed of shoddy TeXing? Take your pick.

That said, if you haven't worked on the source yourself or established things clearly beforehand, well, you probably don't have any automatic legal rights to it. You'll have rights to the end product, the words and the figure - at least until those rights are signed over to the publisher - but not necessarily the source. If a collaboration is to be, you know collaborative, they absolutely should share the code. Yet if they don't, it's not really worth pressing the issue. Just label this colleague as difficult to work with and remember that before considering working on new projects with them.