Aw, that's beautiful! I love the colors and how the drawing has an aged feel to it (if that makes sense). C: I really liked seeing your sketch as well, it gave me some ideas about how to digitally color my own pieces.
While the poses are great and the details refined, the part that stands out the most are the blue birds. The topmost one draws your eye in, the second leads your eye done to the two at the bottom. Really pulls everything together.
cool! I think they gonna be sold at Comitia (tokyo) in May the earliest, summer Comic market in August the latest. there are bunch of other artists, and novelists corroborating, must be fun the person who is taking care of it is building a info page, will let you know once the website is up!