幸せの結晶 is another song that was included in dai's Umineko CD (I don't think it's used in the game)...You can find the
lyrics in his blog.
The vocal version of Hello is also on it, but that's Higurashi...
There's also a vocal version of hope (Ver0.5) sung by the same person who did 幸せの結晶 and 生まれてきてくれてありがとう, but it's probably not official since she did it on her own.