In the Shonen Magazine Edge that released today with the 19th chapter of Nekogahara was also an ad for the upcoming Nekogahara volume 3 (猫ヶ原 3巻). It confirmed the original Japanese release date of June 16th, 2017. The ad also references the same signing event that will occur that Hiroyuki Takei hinted at yesterday. The image used in the ad will most likely be the cover image for the third volume. It will also most likely continue the trend of having the image wrap around to the back cover (and be in color).
Additionally, in the next issue preview for Shonen Magazine Edge, that Nekogahara would also be featured on the cover of the issue releasing next month (June 2017).
Currently the third volume of Nekogahara: Stray Cat Samurai is scheduled for release in English on October 17th, 2017.