Lonewolf_50;
The purpose of my post was to dispel a few popular misperceptions about stalling. As to what did happen, I adopt PJ2's wise words that we simply have to wait for CVR and DFDR to tell us.
As to your first question: "Could stall buffet be mistaken for turbulence associated with a CB?", the stall buffet is preceded (in alternate law) by stall warning, a synthesized voice calling "STALL, STALL, STALL" that continues until the AoA is reduced below that at which it starts. I have no personal experience with stall buffet, but believe that it is unmistakably different from "turbulence associated with a CB". I am aware that the training syllabus of airline pilots does not expose them to anything beyond stall warning (simulators are not representative in that regime), but would expect that an experienced pilot is familiar with the turbulence encountered in CB's.
I do not have the quantitative data that you ask for in the remainder of your post. Some very rough estimates have been made many pages back in this thread.