Whoa, too many subtopics... don't know what to address really...
It's a SWR expansion. You can tell by the name, as it's SWR's name, but with "soku" added to the end of it. Touhou Hisoutensoku
That make sense, according to Garlyle's post all the way back on page 2, Kanako says the big man-shaped thing is a weather phenomenon. For what I understand, it look like some kind of mirror mist-thing that reflects one' shadow... or something like that. It might not be a mech since Cirno sees some great youkai and Meiling sees a giant bird named Peng. Maybe another Celestial caused it... then again anyone could cause it.
I don't think those three are the only ones who'll come out. Seeing the expansion from IMaP to SWR the Touhou fighters roster seem to expand at a decent rate. I know Meiling wasn't in SWR but I thought they would add her in a later patch. Seeing as they were working this, that patch was probably discontinued. Then, again that's just a theory.
Also, curious though why Cirno's silhouette is on the cover...
And about gameplay(of fighting games) and whatnot:
Right now, I'm just happy that Cirno is going to be playable and that Meiling is returning. I'll save my judgement for when it actually gets released.
Yeah, I think so too.