Also at this time of year, the ITCZ can top out out +50 thousand feet, therein allowing Cb's to grow to huge size...
Indeed. As I mentioned yesterday the one near AH5017 grew to just under FL500. Not uncommon for the region.
From what I can see this one also seems to have ejected a lot of 'junk' (presumably ice and sand) into the upper atmosphere. The crash site is right in the region where all this would be slowly descending back to lower altitudes.
No matter if they were a factor in this or not: African CBs are nasty, nasty, things.