Thread:Rrmcklin/@comment-26092473-20151220001035

Source for the birth date (and the name of ban little sister) : http://coffin-of-eternal-darkness.tumblr.com/post/135390435231/side-story-a-day-from-long-ago-ban-nii-ban-nii

And : http://coffin-of-eternal-darkness.tumblr.com/post/135387684551/nnt-style-2016-january-june

http://coffin-of-eternal-darkness.tumblr.com/post/135452397436/2016-nnt-birthdays

I hope it will help you (or ansewered your question) ^^ 