I kept thinking that the Persona 5 "special movie" Blu-ray could be an anime OVA, but I totally forgot that the Persona series actually
has precedence for something like that.
The "special movie" wording they've been using could be apt.
I believe this could happen, however, there's also a chance it'll be a special trailer, too. The reason I say that is because the kanji used in the description for the Blu-ray is "映像" (Full title of the Blu-ray is: "『ペルソナ5』スペシャル映像 Blu-ray") which is also used for the Persona 5 trailers on YouTube. (Example: The 2013 stream teaser has "トレーラー映像" in the title, the TGS teaser has "ティザー映像" in the title, and PV#01 is described as "最新映像" in the video description.) However, I feel your idea would make sense, too, especially since it's a pre-order only Blu-ray. It'd be a good way to introduce us to the story, too. So, I apologize if it sounds like I'm discrediting your idea or anything. Not at all. I find it very interesting. I just wanted to put it out there that there's a chance it could be a special gameplay trailer, too.
That just leaves one question: When will PV#02 be revealed? June? July? I say within the middle of June, right before P4D releases. If so, I'd assume the release date would be October 15, 2015. But, as of lately, I've began to think we might see it within the beginning of July. If so, I'd imagine the release date would probably be November 5, 2015, then. That'd also make sense, if you think about it. It'd also be exactly nine months after PSL2015. We're just going to have to see. The reason I say November 5, 2015 is because it's four months after July, which is typically how ATLUS games are released in Japan; it's usually always four months after the trailer that revealed the release date for it, barring exceptions such as EOU2 and PQ.