I also find it interesting that in the books Secret Techniques of Wing Chun by Author K . T . Chao a student of Yip Man he describes the Snake hand as the Shock Hand or jerking Hand and the Fook Sao as the Monkey hand so where did K.T. Chao get these animal names for his techniques he must have got them from Yip Man .there is a old poetic name that is in the Gu lao Wing Chun called the Cat Washing his Face this same name is in the 18 Arahat kung fu style and Lohan style . I think Yip Man and Yuen Kay San and other old Masters wanted to do away with calling some of there techniques animal names so in the 1930 s 1940 s 1950 s came up with some plain names to call these techniques intsead of animal techniques they did not want there art to imulate animals or the spirit of animals . But to deny that some Wing Chun techniques did not come from animals or animal styles is crazy .
Hawky, you might be right in your suppositions but basically no one is ever going to know. I think there is room for the use of animal imagery (snake, crane, etc.) in WC but I expect the search for any hard links between WC and the animal styles is likely to remain inconclusive.
There’s a “butterfly guard” and a “mata leo” (lion-killer) in Brazilian Jiu Jitsu as well, but I can’t trace that back to a CMA animal style (though some CMA stylists call similar positions to the BJJ guard “tiger suns its belly”).