Based on the current features of the fortooner, it won't have the sliding rear window, it's too narrow for 3 adults in the second row seat, it will have a different rear suspension (the coil springs will be sitting on the rear lower control arms, the shocks are located behind the rear axle with it's upper mount inboard of the ladder frame, the rear anti-sway bar is optional, it has a very pronounced rear sway). so yeah, it will be a huge downgrade.
the Prado is also manufactured in the Hamura plant of Hino motors, not just in Tahara. The Hamura plant also assembled some of the FJCs and the 4Runners/Hilux Surfs.