!) Your looking for Joahcims master, the Great Gama. He can be found in Southhamption I think, and later in Japan. You can learn 2 new attacks, Grandslam, and Deathtron Hammer from Gama. Trick is, equip Leonardos Bear to avoid instant deaths, and try to use Bat form to kill Gama before he does his cheese attacks with the Ring Keys.
Deathtron Hammer BTW = Ownage. Best attack in game overall, and makes combos godlike.
2) Most of the Album Attacks are from the Sidequest bosses, doable right about when Yuri and gang kill Uber Astaroth. If its big, unique, and seems to cast some strange spell you've never heard of at you, then its probally a album picture.
3) The Crests have to be removed and redistrubuted manually, or by the Auto-distribute thing. I didnt really bother, as I used Yuri, Karen, Blanca, and Joachim the entire game and never once touched my casters unless forced. Make Blanca your main healer, get him Arc Heal, Arc Cure, Arc Rage, and Rez, and your set
4) Solomons Key is a giant map which uses the crests (spells) you find as riddles to unlock more power out of them. It is divided into 9 zones which represent the classes the crests come in (Dark, Light, Fire, Water, Earth, Wind, Demon, Angel, Kingdom). Looking over Solomans Map (key), you can see these zones. As you collect crests, see if you have enough crests in a certain category to fill all the slots.
For example, the Ocean is home to all the water themed crests. I think there are 7 total which you can find early in the game. Go into the Ocean area, and read the clues on each crest. Using the clues, look on the map for visual clues as well which combine to tell you which goes where. One Crest might be "Visago, Lord of the Forest, who likes to be by the ocean and his friend Evingas". With that clue, look for a slot in that themed area by the ocean, and near Evingas. Once you place all the crests in the right spots, they unlock the true power of those crests, and your spells get upgrades. A Crest which used to just have heal and rage, will now have Arc Rage or something similar.