Question about Life/Mana Leech

I'm playing a build heavy in projectile damage with Molten Strike, Spectral Throw, Flicker Strike, and the Iron Grip keystone activated.

Iron Grip - "The increase in Physical Damage from Strength applies to Projectile Damage as well as Melee Attacks."

Was going to try Life and Mana leech for the first time. Leech skills generally say something similar to, "0.4% of Physical Attack Damage Leeched as Life/Mana"

Before I make a terrible mistake, I'd like to be sure that this means the damage from these different attacks would contribute to life/mana leech, or if it's simply added to the life leech gemstone.

Thanks in advance!

Yep, getting leech from your passives or gear will apply it to all your skills. The Life Leech and Mana Leech support gems are just alternative sources of leech.

(Random side note: for Molten Strike and similar skills that convert portions of damage to an element, the converted portion won't leech because it is no longer physical damage. You'd need one of the much rarer sources of non-physical leech to leech from that portion.)

Thanks Viperesque!