Ford actually owns 33.4% controlling interest in mazda. This means that while they do not run the day to day operations of Mazda they do control most of the major decisions. Many of the workers at the Mexican plant are American workers (including my uncle) that hace moved there to keep their jobs.
Add that to your calculation of it being a foriegn car.
While the Fusion shares much of the chassis with the Mazda 6 there are several diffrences most notably the frame is slightly longer.
According to my uncle, who works at the assembly finishing plant, the supposed ST model will have the 3.0 V6 with a manual or autostick option.
Hope it is here soon, the 93 SHO is dying a slow death.