The 4th teaser has been uploaded to the site. Some samples of illustrations have also been uploaded. It seems that they will sell them in the June 6th event, in which the manuscript of the manga will be available too. Judging on the image, Chihaya's boobs are the things to be questioned.
Edit : Watched the teaser, and I have a bad feeling. It seems the voice actress for Chihaya is a new one, and her voice doesn't fit his appearance well imo.