Most modern commercial aircraft do indeed have variable stab angle trim.
While part of the elevater is missing, I would say the portion that has the control linkeage is still there (centre section). It's impossible to say whether the missing part of elevater was lost in flight due to the lightning strike or during ground impacts, but I would guess the latter is more likely. Sounds to me like the control cables or linkeage got fried in the strike, however, it is possible that if that portion of elevater was lost in flight (along with the counter-balance) the remaing system could have gone into flutter causing the control linkeage/cables to fail. I'll be looking for the report on this one and the implications to other aircraft with similar control system setups re; lightning strikes.
Glad to hear all are alive, but deeply saddened that some of the injuries are severe. Wishing them all a speedy recovery.
On the face of it, it looks like another brave and skillful effort to land an aircraft with diminished control capabilities in extreme conditions.