If the tail and engines separated at the same time, one would expect the tail to land significantly behind the engines. The tail is subject to a lot more aerodynamic drag per unit mass than the engines. So while the tail will tumble and "flutter" to the ground, the engines will continue on like a pair of rocks, and will wind up quite close to one another. Think of it as trying to throw a feather compared to throwing a rock. Which goes farther?
Also, if it were an "energetic" separation (think kaBOOM!), then the tail section would have had a negative reletive velocity vector applied, making the distance between tail and engines even greater.
My two cents, everthing came apart simultaneously and fell in accordance with aerodynamic drag.
I thought so at first, but the fact that the engines landed within 2 blocks of the frame indicate otherwise. The engines have different weight mass. Assuming horizontal trajectory, wouldn't they have had to land in significantly different location from the frame?