I have a few questions

[Shiki_Lockhart]

1. Animus, novus or nexus make them drop.
2. Saving everything you can to make a relic going faster is possible and nice to do. I am planning to do that myself to save myself some time also to avoid the zerg fever of expansion. What you can save is all 12 atmas, the 3 inks and 75 alexandrite and respective materias for novus, having all 4 zodiac items ready. Books and lights you need to do them on the spot.
3. I don't know. And yes only A and S drop but S drop rate is a lot higher than a A.