As for the new one, we first saw a prototype testing a few months ago, and it was wearing a tweaked version of the new Fiesta body, with obvious changes being big fender flares bolted on and a higher ride height. But now that we've seen the latest iteration in the photos above, we know there was more that had changed on that old prototype. The body had actually been lengthened a bit, which created the strange extension in the rear quarter-window area. This new version uses a normal-length Fiesta body, but it still has the flares and ride height.
Another difference between the two prototypes are the number of studs and lug nuts on each wheel. The old prototype had five-lug wheels and hubs, whereas this latest one uses four lugs. The more recent version with four studs is what we would expect considering the current one uses that configuration, as does the Fiesta both in outgoing and new generations.
Exactly what caused these differences isn't entirely clear. Perhaps Ford was considering a slightly longer version of the EcoSport for additional cargo or passenger space with the older prototype. Maybe Ford was experimenting with heavier-duty hubs and axles for a more off-road ready version of the EcoSport. It may be a while before we start to get answers, since this new-generation EcoSport appears to be in very early stages of testing, considering the repurposed Fiesta body.