I thought it was Iwao and Zhao Sunming who found the Mirrors.
Yes, but Zhao Sunming is Lan Di's own father, so Lan Di knew that Zhao didn't have
either mirror. He killed Iwao and got the (what he thought) one mirror from him, and then was after Zhu Yuanda to get the other one, not realising that Iwao had had both of them.
At the end of
Shenmue Lan Di clearly still thought this, because otherwise why would he leave Yokosuka?
And what is the connection with the blind/not-blind guy? Is he going to have a further part to play, as the friend of Zhu, Zhao and Iwao?