What I see in these pictures is
The weight distribution seems a bit different in some, not all, of the postures for starters.
Yang Chengfu (YC) appears to have his weight less evenly distributed. More weight on either the front or rear leg. Where Tung Ying Chieh (TYC) appears to have a more centered weight distribution. This is not saying either is wrong, if you look at the position of the feet in some of the postures, particularly the back foot, you can see that they are using a different angle of force. YC has his foot at 90 degrees which gives him a rather straight line of force and I can imagine it would have been a whole lot of force. Where TYC has his foot at a 45 degree angle and his body is facing much more forward than YC. I know from experience that this is also a whole lot of force, but possibly not as much as you get from the 90 degree footing and more of a sideways facing stance (but to be honest I do not want to bee the test subject that finds out either). However I tend to feel that TYC is in better position should that application fail or if three is a need to move in a different direction due to the changes that occur rather rapidly in a fight. But admittedly it is possible that I am a bit prejudice here since my line comes from TYC and I never trained with the Yang family.
YC tends to have a higher stance in many of the postures where TYC tends to be lower. Almost as if TYC is doing a slightly smaller frame or, if I am brave enough to post this on an open forum, something like a Chen style, but not quite as low.(donÂ’t tell my Sifu I said that)
YC hand positions appear to be higher in some postures than TYC and it appears that TYC might be in a better position as far as fighting goes, but that is debatable. I see my Sifu in postures much like this (TYC) and I have experienced the power he can emanate from them (fajing) and that is what I see here in TYCÂ’s postures, relaxed and ready. It appears that YC is not as relaxed in some of the postures but I have NO doubt that has a lot to do with being close to 300 pounds, however I also have no doubt there is a whole lot of power there that I would not want to be on the receiving end of. As my Sifu would likely say TYC appears to be more centered, rounded and ready. But again this could be the effect of the body weight differences too.
I did discuss these pictures with my Sifu (although he had not seen them when we last talked) and his first comment was the YC was around 300 ponds when he died so you would see differences in the postures. Also you have to take into account that per TYC great grandson, Alex Dong, TYC did study some Hao style first and kept in contact with his Hao style Sifu after he became a student of YC. However he did not teach Hao style nor did my Sifu ever see TYC do any Hao style at all.