Small package freight debris is going to be dispersed rapidly by wind and current, and a full analysis of their location and time since event would be needed to work out whether they have been liberated in flight. The B767 has had only two in flight events with a rapid descent to impact; Lauda 004 and Egypt Air 990. Lauda was from a structural failure resulting from uncommanded TR deployment on the LH PW4060 engine, resulting in overload of the vertical stab, and a torsional failure of the tail and a rapid overload in negative g of the wings. Egypt Air was.... disconcerting and remains disputed along national lines. The event timeline however is compelling and similar events have occurred far too often in the industry. The B767 has had it's fair share of AD's on the stabiliser and the attachment structure going back more than 20 years. The CF6 engine on the 76 has had it's fair share of uncontained failures. Gust front related overload is raised due to the existing weather that was being avoided/penetrated, but would not by itself have led to an overload of the system, and 18 years after AA587 the industry is more aware of the impact of rudder doublets. The debris trail of large components will be telling.
R.I.P.