I suppose this is somewhat relevant...
Manga title page (scanlation in progress)
Live-action movie preview that was also announced in that issue.
The LA movie does not have the "Natsu no Sora" subtitle, but it's still about Suzuki Sora, not Yume or Nami.
If it's airing in summer, the manga won't be getting much of a head start. I can't help but wonder how this triple release will work out.