I have ordered my rear disc brake assembly from Japan. It will be taken off a wrecked LC95 Prado.
I have checked with the Toyota EPC and it looks like it's a direct bolt-on. The assembly is a disc/drum combo.
There's no need to replace other items other than the existing drum brake.
The cables, ABS (including sensor), and the master cylinder are the same.
For those in the US, I think you can use the 4th gen's rear brake assembly. It's the same as that of the LC120 Prado, which by the way, is still the same as that of the LC95.
HTH.