I haven’t seen the Gin Soon Chu version of the form, so I can’t comment on any of the features you mention. I am aware that Yang Zhenduo teaches the Hit Tiger forms differently, but the main difference is that in his version, the ending postures of Left and Right Hit Tiger face cardinal north and south, while other received versions align on a bias, facing into the corner directions northwest and southeast. This necessarily makes the footwork different (with, for example a larger angled step to the left rear in the bias version), but not, in my own experience, dramatically so. I learned to do the Hit Tiger forms aligned on a bias from my first sifu, which is the way Fu Zhongwen and Yang Zhenji both depicted it in their books. Somewhere on this site is a link to a pdf document of Dong Yingjie’s form photos, and they also show the bias arrangement of the Hit Tiger forms.
In studying Yang Chengfu’s 1934 book, _Taijiquan tiyong quanshu_, I discovered some interesting things about the description of the Hit Tiger forms. The written description clearly indicates an alignment on the bias, with the ending postures facing into “the corner of the square.” However, the photos of Yang Chengfu in this book are taken in a room with a patterned carpet. If one goes by the lines in the carpet in the Hit Tiger Forms photos, Yang Chengfu is evidently aligned to cardinal north and south, not on the bias. Now based on the photo evidence alone, I can’t assume that the photos were taken of Yang’s form in real time, and that all of the ending postures are depicted as they would be in a form “in progress.” It’s more likely, given the state of photography at that time, that the postures were photographed as separate fixed poses, or as ending postures in brief discrete segments of form performances, with the directionality determined by the best camera angle rather then by the actual course of the form. However, in comparing the form narratives of _Taijiquan tiyong quanshu_ with Yang’s earlier 1931 book, _Taijiquan Shiyongfa_, I noticed that the description in the earlier book did not have any wording that would suggest an oblique alignment, and instead of facing into the corner of the square, one is instructed to face “the side of the square” in the ending postures. The photos for both books, by the way, are exactly the same.
Why the difference in Yang Chengfu’s descriptions in the two books? I don’t know, but there are several possibilities. He may have originally taught it one way, then later changed it. Or, one or the other description (which may have relied on the class notes of his students) could have been inaccurate. Another possibility is that Yang Chengfu taught variant ways of doing Hit Tiger, resulting sometimes in north south, sometimes in northwest-southeast alignment. The standardization of a movement art in written documentation, keep in mind, is somewhat artificial.
This probably doesn’t directly address the issues you have in mind, but it shows that there is some variance in the interpretation of the Hit Tiger sequence.