Help me understand some general damage math in the game. I'm stuck on basics.

Let's say I want to scale Molten Blast. It has the following info:
-Attack
-AOE, Projectile, Fire
-Requires Two Hand Mace, One Hand Mace
-Converts 60% of physical damage to fire damage, explodes on collision, damages and scatters shrapnel behind it. Shrapnel converts 100% of physical damage to fire damage, and fires 8 projectiles.

For the following questions, assume I'm wielding a Two Hand Mace. Tell me if I'm missing someething, or I'm on the right track assuming all things in the game are working as intended.

1. I take a '10% increased projectile damage' node. My assumption is that I get 10% increased damage to both the initial projectile, and the shrapnel.

2. I take a '12% increased physical damage' node. My assumption is I get 12%*.6 = 7.2% increased damage to the initial projectile, and 12% increased to the shrapnel.

3. I take a '12% increased damage with two handed weapons' node. My assumption is I get 12% increased damage to the initial projectile, and 12% increased to the shrapnel.

4. I take a '12% increased fire damage' node. My assumption is I get 12%*.6 = 7.2% increased damage to the initial projectile, and 12% increased to the shrapnel.

5. I take a 'Gain 12% of physical damage as extra fire damage' node. My assumption is I get 12%*.72 = 8.64% increased damage to the initial projectile, and 12% increased to the shrapnel.


Assume I'm also using Fire Wall. Fire Wall has the following info:
- Spell
- AoE, Fire, Duration

My assumptions are:
1. It doesn't benefit from the projectile damage bonuses as it's not a projectile. Things fired through it will gain the added fire damage.
2. It doesn't benefit from the physical damage bonus as there's no physical conversion.
3. Does it gain the two handed weapons bonus? I'm still wielding a two handed weapon, but this is a spell, not an attack. POE1 was all about attacks.
4. It does gain the increased fire damage as it has the fire keyword.
5. It doesn't gain the extra fire damage, as there's no physical conversion.

The two handed weapon nodes seem busted with inspect right now, so I'm unsure.