I think there are some errors:
the puzzle Lloyd 600 convertible was built in 1957 according to Peter Michels' book,
the last picture does not show a Lloyd 400, because the turning lights and rear lights surely are from the Lloyd 600 as well as the front wings (no provisions made for the Lloyd 400 turning lights beneath the headlights), chrome trim and bumpers without overriders just like the Lloyd Alexander (appeared in 1957), so it shouldn't be 1954 either as the visible door hinges just disappeared at the end of 1954. Last but not least the red license plate is numerically very close to the one on the later car. My guess would be that it was a first try or an earlier version of the 1957 car just built around then, too.