R.m.Bakker, so you're the author behind that article? Thank you very much for taking the time to compile all of that. It has been incredibly insightful! I also really appreciate the advice about the sleeve cap. One thing I'm still uncertain about though is how to draft the correct sleeve cap shape. I think I need to spend even more time thinking about and analyzing all of that information though to fully understand how to apply it. I do of course appreciate the idea of thinking about one problem at a time and trying to find the solution for that specific issue.
Speaking of one problem at a time, I have sewn together a quick revision taking into account splitting the body from the yoke and introducing additional fabric there. I have also added ease to the side seams per your recommendation, Posaune. I also dropped both armscyes 0.5cm. I have not yet modified the pattern specifically for my left shoulder as I first wanted to sort out the yoke and ease issues. From the new photos, it still appears as if I don't have enough fabric both in the front and back over my chest and shoulder blades but I'm not certain about it. Beyond that, I'm not sure where to next direct my focus. Should I now go about fitting my left should or are there more pressing issues? Just for reference, there is no seam allowance in the armscyes or neck.