Borrowing a page from PJ's playbook here.
The Cheun Jen 7 Disciples were, as a group, prominent characters in L/ROCH, but individually, they were by no means equally represented. The most prominently represented, of course, was Yau Chui Gei...who was a major character in LOCH, ROCH, and even had a namecheck at the very beginning of HSDS. After that came Ma Yuk, who probably had the second most appearances among the 7 Disciples and is famous for having taught Gwok Jing the basics of inner power. Wong Chui 1 was featured somewhat prominently (although less than Yau and Ma) in the middle of LOCH, and he was also known for being the teacher of the traitor Chiu Tze Ging in ROCH. Gok Dai Tung became known for killing Granny Sheun. Sheun But Yee was the only woman among the seven, and she was known as the teacher of Ching Yiu Ga. Tam Chui Deun died, but his death sort of immortalized his name. He was the reason that the remaining Cheun Jen Disciples sought out that confrontation with East Heretic Wong Yerk See, after all.
That leaves Lau Chui Yin. This guy did nothing notable to distinguish him from his six colleagues during LOCH or ROCH. He was just sort of filling out that seventh space. Is Lau Chui Yin the ELOC of the Cheun Jen 7 Disciples? Is there anything special to distinguish him from the other six disciples?