This is super late guys, but I only recently got into Fate Kaleid Liner and I'm about half done with season 2. There's a certain instrumental track that plays during emotional scenes in both season 1 and 2, but I know for sure it's in episode 6 of season 2 around 18:30. I tried looking on Youtube and all and I'm half certain it's Shoujo ha Tokini Omoinayam
but I'm not 100% sure and if anyone could verify that would be wonderful, thanks!