This almost vertical climb right after TO is puzzling and it is what I believe they are keying in on. A loss of an engine after lift off would not normally lead to a pitch up. As I remember the earlier versions of the 1900 (A and C), it is aft CG critical. This is sounding more and more like either improper baggage/cargo loading or shifting of the b/c after TO. Don't know about the D model but with the A and C, if the airplane was loaded in an out of CG (aft), you could tell when you started to taxi.