Yup. We are saying the same thing. The blue that I marked in the picture have to be window braces. This is due to the fact, that the top woofer is using the port above that brace. If it was solid, that port would not be doing anything. So according to the drawing, the first cavity is the slanted (part of the yellow) brace along with the sides and front baffle to house the midrange and the tweeter. The following three are indicated in the yellow, orange and green.
My assumption is the small space between the orange (marked blue) is a small window brace. This is the only thing that makes sense. It wouldn’t make sense for it to be empty space there for a lot of reasons. In the end, I believe we are saying the same thing about the cavities. 4 in total.