well i got all mp3 320k but i can't find flac anywhere.
Souta Takanashi
http://koe.anime-sharing.com/anime-ost/working-character-song-menu-1-souta-takanashi-1675/
Taneshima Popura
http://koe.anime-sharing.com/anime-ost/working-character-song-menu-2-taneshima-popura-1680/
Inami Mahiru...