It's been a while since I last read everything but IIRC Tex was the one with the gun right...was there any others? If it was only one, it is possible that Bruce may have been able to disarm him. The same goes with the knives. I recall watching one of his demo vids years ago where he was surrounded by a bunch of guys carrying melee weapons and he managed to disarm every one of them. Would he have been able to do it that night if he was there? it's something that we will never know and as you say is just another of the endless what ifs.
As for the trailer, it looks good. From what I've read about the film, they don't get everything right about what happened that night...some of the actors look wrong, bits are added that didn't happen etc but the majority who go to watch it won't know the ins and outs like we do so it won't matter that much. The guy who plays Bruce is called Mike Moh and he is proficient in Martial Arts so they did really well landing him.