Some questions on quests I'm stuck on:

1. I've got Rockshatter, but haven't found Maeva. Which city is she in?
2. For the Mythic Dawn quest, I'm at the part where I've killed the guys in Bruma and I've found the Basement Key, but dunno where to proceed.
3. For the missing painting quest, I'm up to the part where I find the painting supplies in Chanel's desk, but dunno how to proceed either.
4. I killed Umbra, but I don't have a Soul Stone big enough to trap anyone's soul. Best I have is a Grand Soul Gem, what do I need?