I can't imagine why you wouldn't be able to install one. The real trick will be if the wiring harness for it is preinstalled or not. If it is then it would be a simple bolt in mod but if not then it will be more involved.
Never mind, I didn't realize that the Lariat trim doesn't come with a power passenger side seat even with the Lux package. The Lariat never interested me so I never speced one out.
If this is the case then adding a power passenger seat will be difficult.
Unless they had planned to include one but dropped it due to constraints. In that case there may be power available somewhere waiting for the seat. Anyone much smarter than I know?