Fireball projectile damage vs explosion damage

i have read in a couple of threads that fireball has 2 components. first is the projectile damage then the explosion damage. does anyone know what % each of the components takes up? basically i am wanting to know if peirce would add more damage than concentrated effect for fire ball.

do auras like anger apply to spells like fireball?

and i noticed burning damage has its own passive skill tree slots, does normal increased fire damage also affect burning damage?

From my experience as a lvl 65 fire witch, the fireball damage and explosion damage are the same. The fireball hits your intended target and if any enemies are nearby they take the same damage as "explosion" damage.

[Note that "explosion" damage is affected by "increased radius and area damage" nodes. So in some cases the "explosion" damage is more than the fireball hit damage.] - Whether this is correct i am not 100% sure. I could be incorrect because the support gem "Concentrated Effect" increases Fireball damage although it does not show on the tooltip.

Auras such as Anger/Hatred/Wrath do not apply to spells, only to attacks that require weapons.

The more spell damage you have the more burning damage is done i believe. At least from my experience it is definitely the case.

An interesting build could be going "Chance to Ignite" gem with burning damage nodes and bypassing spell damage nodes, requiring you to ignite (dealing burning damage) to kill targets. Could be interesting albeit impractical.

the burning damage is based off of the initial damage dealt so yes increasing your fire/spell will in turn increase your burning damage

i'm not sure if i'm missing an item or a slot on the tree, but with all nearby talent points and searing touch it's possible to achieve 150% or more additional burning damage

you can add damage to fireball using support gems such as added lightning/chaos damage as well