Is there any evidence that these two are really two different people ?

Or, on the other hand, could they be several different people ?

if they are all the same, hopefully there are enough appearances for an ID.

http://hkmdb.com/db/people/view.mhtml?i ... ay_set=eng

http://hkmdb.com/db/people/view.mhtml?i ... ay_set=eng

The credits of Siu Sei for "Crazy Partner", "Avenging Eagle" and "Swift Sword" belong all to Austin Wai. Wai is credited with that name in the three movies (I thought first the name in the "Eagle" and "Swift" cast lists looks like Siu Tin. But in "Crazy" the name is good to read).
If nobody objects I merge Siu Sei (2) with Austin Wai in a few days and delete Siu Sei (1) from the cast lists of "Eagle" and "Swift".

Done.