Great Work Greybeard! The HF was most likely operational until 0214z (we say this, because of the absence of a LRU ACARS message of it being faulted). Therefore, the vertical stablizer was intact and had not left the airplane before 0214z.
This Means that the ACARS messages probably preceded the fatal loss of control event.
Does the HF antenna provide an specific input for fault detection or the lack of the HF antenna would be detected by the absence of (constant and periodical) inputs in a given buffer outside the rudder ?