I love how Persona 5 is to far-fetched for you guys, but persona dancing is pretty much guaranteed. I believe someone wrote that it would be a waste of time to show such a niche Japanese game such as P5, but dancing can totally happen.
Just looked closer at the image. That is without a doubt Persona dancing. So Atlus Japan showing a persona game is confirmed. Why show up with just a dancing game when you can show up with your main dancer?
To be fair, we were talking about showing at Sony's conference, not just E3.