I'm sorry if I make you angry, but I think the actor at the three images don't look like Tong Gaai.
He is credited as "hatched man" in HKFA. Can he be another gang member who is not at the images? Unfortunately I don't have the movie.
Not angry, just trying to follow your original train of thought.
Tong Gai is the only main minor character in the film. So are you saying he doesn't look like other images of him from the same time frame, or in comparison to something else?
First of all after I saw the images I immediately thought that the actor is not Tong Gaai and was sure that it is another actor. I'm familiar with Tong Gaai and seen him in many movies.
One difference you can notice from the actor at the "Charming Little Bird" images and Tong Gaai is that the "Charming" actor has a mole or something like that under his right eye. I don't see that mole at the other Tong Gaai images and in the three movies I checked yesterday with Tong from that time.
Maybe another editor can say his opinion on that matter. It is always good to hear a third opinion.
I'm open to the possibility that it's not Tong Gai. I'll see if I can dig up the on screen credits and can check to see if he prominently credited or not. Perhaps he is just an minor extra/goon elsewhere in the film.
After looking at it carefully, I also think that this picture is not Tong Gai. Dennis, the guy in this picture looks a lot like someone you were in inquiring about in a thread recently.