1) For magic.
2) By default:
- Attack/Select: Z
- Skip Scene: X
- Jump: C
- Show Status: V (Close with Z)
- Guard: S
- Switch Between Items: Hold X, Press A to switch.
- Switch Between Magic: F
- Use Magic: D
3) No idea what section you are talking about.
4) In town. The first town is after meeting the purple orc.
- Talk to the item shop to buy items.
- Talk to the purple orc to set status points.
- Talk to the black bat familiar to set magic/skill points (using same status points).
- Last skill is how to get the double/triple combo attacks when pressing Z. The others are magic.
- 2nd to last skill is a bat summon, which can be used to clear those black wall-like things blocking collectable shards.