So all elemental damage are raw +X ele, coming from gear. Famine or Gimmershred, RbF, charms, TG, Highlord, Raven.
Except enchant, from Lava gout, and Diablo's firestorm, from Torch.
Ok.

Given the "low" amount of elemental you can reach, I guess Conviction is more usefull for -%defense than for -%ele res.

It is true that Torch's firestorm + high conviction owns, even in Hell (as long as no Fire Immune).
It's clear on my dreamdin, when zealing a 130+ light res with a 25% Torch.

Ok.
Good guide, interesting. And everything no CC is welcomed in my eyes.

Now may I ask if you wouldnt be better with another weapon and 37 x elemental small charms (up to 2-99 light each, didn't check for fire/cold) ?
What are the purpose of combat skillers ? +%ar on zeal ??

Famine gives some ele damage, but no more than, let's say, a simple Djinn slayer (250-500 fire), or Azurewrath (250-500 cold + magic).
Both faster than berzerker axe. Or is it for the +2range on BA??
If physical plays a part in your build, then why not use Grief + tons of elemental charms ??

Also you try to marry elemental (when zeal) + smite... I dont believe they go well one with another.

Enough ramble on.
Your guide is good. Can hardly be improved. But I'm just not convinced by the basic idea.