Very cool, love that window lid model!!! I noticed this machine doesn't have ridges on the upper circulator column of the agitator, whereas the similar Oasis does.
As for the agitator/disk being interchangeable, I can't see why not. F&P uses a low post drive, and the disk is fairly high in the center, higher than it would be for a normal wash impeller. I pulled the cap off and found the familiar Kenmore 7/16" agitator mounting nut.
Just my 2 cents.