I think I read somewhere that Yin and Shi were cousins but maybe they were just friends.Hi K-man
I don't know to much about Shi Baguazhang its not as popular as Yin,Gao,Cheng,Liang. I am sure Shi learned alot from Yin since he was the most senior student. It might have been possible a student of Shi picked up some Yin and mix and match. If you find where you read that information it would be cool to know, maybe Yin being Dong's first student had more pull on other of Dong's student then previous thought.
http://wulinmingshi.wordpress.com/category/shi-style-baguazhang/