One thing about Sai Mun Chui Sheut in LUK SIU FUNG is that he inspired a number of "wannabes" who tried to dress/act like him, but couldn't match the original (in terms of swordsmanship or personality). This excludes Yip Goo Sing, whom I believe predated Sai Mun Chui Sheut (Yip was older and began practicing swordsmanship first) and independently became a similar figure. Let's get down a list of the "wannabes"
To my knowledge:
1. Yip Goo Hung: the younger cousin of Yip Goo Sing whom Luk Siu Fung encountered outside the Haunted Valley.
2. I think there was some kid swordsman who also dressed and acted like Sai Mun Chui Sheut.
3. I don't know if there's an equivalent character in the novels, but in TVB's THE NEW ADVENTURES OF LUK SIU FUNG (1986), there was a character named "Ngok Yeung" who was a Sai Mun Chui Sheut wannabe.
4. From time to time, it seemed like random nameless nobodies showed up who dressed and tried to act like Sai Mun Chui Sheut until something embarrassing happened to them.