VFD, extending the gear after it had been selected UP would be the last thing on any pilot's mind at that point nor is it a procedure to ever do anything on takeoff with the gear except to retract it.
If a load shift caused this crash it probably happened as the aircraft rotated and left the ground. At that point the nose would have continued to rise beyond the 11-1/2 to 12 degrees of normal pitch and at a much more rapid rate of pitch increase than is normal.
The PF would have attempted to arrest the increasing pitch rate and increasing pitch attitude with as much forward pressure on the yoke as he could muster as well as applying nose-down trim.
Most likely, the PNF would immediately also help by trying to push the nose down and possibly applying nose-down trim as well.
There would have been no time, no free hand and no thought of extending the gear in this tragic and preventable situation.
These guys were fighting to get the nose down and avoid stalling the aircraft. It looks like they tried valiantly.