Now, I have a question for both you and
Slender
: did you guys have to crop and zoom your recreations down to just the upper body after the fact, or did you do that within Smash 4? Because I tried to recreate it too, and found the right spot, but I couldn't zoom in close enough. Granted, I am woefully unfamiliar with Smash 4's camera system, so the option may be there. But my point is that, if you can't zoom in that close, could the leak really be a screenshot taken by the team (for the site, say?)
It's also notable that you can't get that kind of angle on the water in normal gameplay, so this would HAVE to be a pause screen snapshot at best. And I do believe any pictures on the site are taken with the in-game camera. So can it zoom that close, or did someone crop the leak?
Edit: also notable, as
BluePikmin11
suggested, it's a little hard for this to be a cutscene, considering the exact angle the camera must be at to achieve that water/sky level. I can't envision a cutscene taking place in such an area of Delfino--they'd likely use the main plaza in that case.