I think it just boils down to - the FFA can find no flying speed so slow that directional control can be lost due to an engine failure ("VMC" < VSo) and that automated corrections via the yaw damper/rudder, and FADEC, mean that the loss of an engine requires no particular pilot inputs to maintain direction control in the event of engine loss at higher speed.
The 550 engines are fairly small and low-thrust (900-1100 lbft) and are mounted on short pylons on a fuselage that also skinnies down very rapidly (thrust lever arm ~1.17m - only slightly wider that the cabin exterior). The VS and rudder are large (and on the upgrade "Canada" there is a centerline strake or VSTAB below the fuselage as well). There may be other less obvious aerodynamic effects that minimize SE yaw (tadpole fuselage, cranked wing that technically has a forward sweep, on the mean chord line).
I do note that the engines are to be brought up to a stabilized 50% on each side before brake release - just to be sure one doesn't perform a ground loop at zero airspeed.
CANADA Specs