Hmmmmm. Marked your analysis in PURPLE. Is this about right?
You are missing what is going on in this picture, two of the three Saudis are in the front of the picture next to the man in the orange coat with white cap. The third Saudi is in the left bottom corner by the wall in front of the black woman in the green shirt. He still has the backpack on. What is he doing over there? That is the approximate location of the second bomb. In one of the photos I have seen, it shows the second Saudi(in front of picture) looking back in the direction the third Saudi is coming from. Also, the taller one with the yellow stripes on his jacket, is constantly fiddling with his hands. This is a sign of worry. The picture with all three confirms they are together. The older man in the large parka with glasses is carrying a cane. I do not believe he is involved.