IIRC, there was a song at the end of the first episode (only the first) which was not this one, but maybe I'm wrong though . Did you lsiten to the Astral no Mina-san version of Aruiteikou? It's a very good version too . I recognized him when he took his usual voice during the scenes when itsuki uses his "daemon/dragon" eye ^^. Adelicia was my favorite female character in this show
The G00 OP (images+music) was indeed very good.
Ef tales of memories? I watched it but I don't remember the opening at all ^^""""" And I don't even know what Melodies is ?_?