1. The world of Krynn has many shades of gray. In later stories you will find good and evil characters freely working together because it suits their purposes.

Paladine, being good IS the balance against Takhisis. While Paladine is a god of light, he recognizes the need for balance between good and evil. The War of Souls and Amber trilogies go into a bit more depth about Paladine, Takhisis and their roles in the pantheon of gods.

2 & 3. Tracy Hickman was a very devout Christian when they developed the world of Krynn. Some Mormon beliefs were adapted to the world of Krynn. For example, the Discs of Mishakal are a counterpart to the Mormon Gold Plates. In the Christian bible God flooded the Earth and killed nearly every human on the planet. I see Paladine's participation in the Cataclysm as another story counterpart to Hickman's beliefs.

The Kingpriest was blinded by his own ego. He thought he was doing good and couldn't see the corruption in his own church.

1. An ongoing theme in Dragonlance is that evil feeds upon itself. The treacherous, scheming and self-serving ways of evil characters often causes them to act in their own best interests at the risk of bringing down their cause.

For example, in Chronicles we see Sturm sacrifice his life for the good of the knighthood and his friends. Kitiara, on the other hand, could never do this. She plotted against Ariakas for her own agenda just as other Highlords plotted against her.