Speaking about the Toro and Riv, I would not even consider anything else than a 71-73 boat tail Riviera.
Of those five Imps, I prefer the 61 Crown over the 57-60. The fins are after all smoother in my eyes. Yes, they´re higher than the older ones, but the back edge of them is sort of flowing instead of being axed to be close to end vertically straight and the front end is unique among luxury cars or any other passenger cars offered back in the day: free-standing head lights mounted to cavities, the turn signals/parking lamps over them in the sheet metal and the narrow grille consisting of horizontal bars. The side trim seems to belong to a luxury car by its size, styling and the detail at the bottom of the fin.