Is it possible to add a passenger side power seat?

Get one from Japan or other RHD market?

 

are the passenger and drivers seats different?

 

I'm not sure what all of the specific differences would be, but at a minimum switches and airbags would be on the opposite side.

You really need to look at schematics and part numbers and do a comparison. It's possible several of the parts are the same and you could just purchase the components that you need. I tried to do that before I bought mine for the driver side. I have the schematics, but not the part numbers as Toyota makes it much harder to search online compared to Honda. For my driver seat, my hope is that the cushions, air bag and covers remain the same and it just requires a different frame assembly, power harness, switches and trim piece.

 

Have you guys done the project?