"The drag from this should have caused some decelleration, and possibly
loss of altitude - was this the case?"
ASO, Neither happened while the FDR was working. After that the radar data
is confusing (I think).
Picky, the vertical line in the synchronization chart that passes through
your point 7 is described only in Chinese. Earlier in this thread Peanut
Butter said that the break-up occured 26s after the CVR stopped and this
line comes 26s after. Point 7, of course, requires explanation.