My 95% statement is to reflect on how important the two sets are. WCK is basically Tan, Bong and Fuk. Sure 90% is okay. Statistics like that are just someone's estimation. 95% of statistics is made up on the spot, including my statement.
As for your questions:
Well grabbing the back of neck which is done in Wooden Dummy - This is found as the Double Chuen Kiu Sao opening of Chum Kiu
Gan Sau and Kwun sau technique done on the dummy? - Simply use the outside Fuk and replace the hand with a diagonal Jum Sao, which creates the upper Jaam Sao, and of course, you have Gaun Sao in SNT...Kwun Sao is just a combo of shifting Bong Sao and upper Tan Sao
Huen Sau cycle done on the dummy? - Huen Sao is in every set of WCK...simply alternate left and right while using CK shifts...
Grabbing the arm while kicking the shin on the dummy? - Every step is a kick, and you have double Lop Sao in SNT and CK...
Right and left hooks done in Bil Gee? - Variations of double Lan Sao with the fist, instead of open hands.
Grabbing between the legs done in Bil Gee? - Simply bend down while holding hands in a double Wu Sao position...
Diagonal downward elbow strikes? - A variation of Chum Kiu's Pai Jang, done downwardly..
See? All the above is in SNT and CK, just minor variations. When you are technique based, instead of concept and principle based, you get screwed up and think its all different...
But there must be reason why their are separate forms and Sup Yee San Sik? - Yeah, its called a teaching methodology and curriculum...
What system is the Luk Dim Boon based off of? - The pole is based on the Su Lam system as it uses a different power base, stances, and movement. As we know from history and lore, it was appended to WCK.
Your analogy of dictionary and encyclopedia are not quite correct in this context.