I have no answers for you on your specific question. What I can add is that most "named" styles of TCC were not named by their creator, but rather by their students who named them AFTER their "creator".
The way this was explained to me is the naming of the differing styles is a natural progression from one "style" to the next based on the students of differing masters talking to one another and saying things like, "Master Yang's style of TCC is very fluid and graceful, yet powerful." and then having a response such as, "Yes, and Master Sun's style is so compact and versatile."
This lead to style names being attributed to the differing masters styles of practicing and teaching.
So now we have Chen, Yang, Sun, Wu, Wu/Hoa/Li, Tung, etc, etc, etc, ad nauseum.
Truth be told, it's all the same thing. What you have are, as the Grand Master so elegantly states the case, differing flavors of the same basic dish.
They all come from the same basic food type, but have been seasoned with different spices. The result is that while they look and taste slightly different, underneath they were all the same to begin with.
To give you a minor, modern, idea of how this works:
My form looks very different from my instructors forms.
We study the same form, further I study and practice the form as he taught me. You would think we would look just the same doing the same form side by side.
But we don't.
For various reasons beyond our control we all move in different ways. There are many reasons for this.
We are different heights, Bill is 6 foot something and I'm only 5'7".
Our legs are different lengths, our arms are different lengths, our torsos are different sizes.
For these reasons and more, we couldn't possibly move in the exact same way, we're not built alike.
Yet the TCC we practice is the same, down at it's root.
His skill is, of course, more advanced than mine in the Yang style, as he has much more experience with this flavor of TCC. He knows more of the subltle movements, more of the deep chi integration, that sort of thing. Therefor he is going to move in a more precise manner than I can now, and probably always will because he will always be that far ahead of me in the study and practice.
I'm from Detroit, I have no idea where Bill is from originally, but he's not from Detroit. Geographic location, things like urban settings vs. rural settings, are going to give you a differing viewpoint on life, a differing level of natural tenseness in your body, you will walk and talk differently and display a differing personality.
All of these types of things, and many more we can't even imagine, that make us who we are as individuals are going to influence our movement patterns and thought processes.
One more item I can think of, I practice TCC as a martial art, first and foremost, due to my mindset, background, interests. Others in the same classes as me, taking the same instruction from the same teacher, are not the least bit interested in the martial arts aspects of TCC and study and practice strictly to achieve the health benefits of the art. We are not going to perform the same form in the same way. I will be emphasizing the martial aspects, thinking clearly of the application of each movement as a martial movement actualy being applied against an opponent, they are going to be thinking of how to best move to generate and move chi to give them maximum benefit to their health.
Our mind intent for each movement is going to be completely different, so our external look is not going to be the same for each movement.
Now do you see how the differing "styles" of TCC came about and then got different names?
I don't know wether the Grand Master Yang Lu Chan referred to his TCC style by a name, maybe he did, maybe he just called it Tai Chi Chuan, or maybe he called it something completely different.
It makes no difference.
What is important is that his students called it "Yang style", we continue to refer to it as "Yang style", and so that is what it became.
I would imagine it wouldn't be that far fetched an idea that one day we may end up with a style known as "Ma" style TCC, from Master Ma Yeuh Liang. He practiced and taught Wu style, from the Wu Chien Chuan lineage. He was a disciple of Wu Chien Chuan, who was a disciple of Chuan Yau, who was a disciple of Yang Lu Chan and his son, Yang Ban Hou.
Wu Chien Chuan, as far as I've ever heard, did not refer to his style as Wu style TCC, but his students did. Wu Chien Chuan learned his art from Chuan Yau, who most definitely practiced Yang style TCC. Wu Chien Chuan, the son of Chuan Yau by the by, then modified the form to suit his own needs. While it still retained the underlying principles of Yang style TCC it was much more compact, smaller. He taught for a time with Yang Cheng Fu, and they had students in the same school. Their forms were different, but they taught the same principles.
Their students then, naturaly, began to refer to Master Wu's style or Master Yang's style of TCC, to keep them seperate.
There you have it, a "style" is born.
Wu Chien Chuan then taught Ma Yueh Liang, along with many other disciples and sons. Master Ma taught the Wu style to his students, just as he learned it from Wu Chien Chuan. Wu Chien Chuan's sons, Wu Kung Yi and Wu Kung Cho, then changed the form of their father and made a square, or articulated, version of TCC that is now still being referred to as Wu style.
Master Ma still taught the round forms to his students.
Both are Wu style TCC, but...
Now there is round, square, large and small framed Wu styles.
Since Master Ma taught only the round small frame forms, I would imagine his students might one day begin to refer to them as "Master Ma's style" to keep them seperate from those of the brothers Wu and another lineage may be born.
What I'm trying to get at with this long, rambling post is that it's the students and proponents of a style who name it, most of the time after the particular masters death who "created" his version of a TCC form, not the master himself.
Again, I don't know for sure, but I would imagine that Yang Lu Chan did not call his forms Yang style TCC, but that his students most definitely did.
Maybe Master Yang Jun would know?