Unlimited Fire Elemental OTK (or APM Shaman)

I am trying to theorycraft a Shaman OTK deck, using Corrupt the Waters, Fire Plume Harbinger, Grumble, Worldshaker, Zola the Gorgon and Fire Elemental. Together it is possible to kill any warrior or Druid (if you can click fast enough) for 8 mana only, with only the quest completed as the setup:

The core is set, but the cards around are sub-optimal. Anyone want to help building a deck which can survive until combo completion?

Yo, I literally just theorycrafted the exact same thing. Same mana cost, everything. Then I went looking to see if anyone had done the same. Glad to see someone else sees this as well.

Fe,Fx2,Z,G - 5 cards total

Fe = Fire Elemental

F = Fire Plume Harbinger

Z = Zola

G = Grumble

HP = Hero Power (Corrupt the Waters' reward, your hero power becomes "your battlecries trigger twice this turn")

F[x]; x = mana cost of the card

Z[x](y); y = the card that is bounced back

HP[2]-F[2]-Z[3](F)-F[0]-F[0]-G[0]-Z[1](G)-F[0]-F[0]-F[0]-G[0]-F[0]-Fe[0]-G[0]-F[0]-{{Fe[0]-G[0]-F[0]}}

Repeat {{x}} until they die

(8 total mana used for infinite damage when you target face with every Fe battlecry)

As for the surrounding deck, I think you can fit this 5 card combo into another separate established deck. Plugging it into control shaman, (except you CAN'T use Hagatha cause her card generation would clog your hand, as I'm sure you already know) is my best bet. But also, I'd specifically find ways to tutor out the combo. So to do that, I'd run Sand Binder to Tudor the elementals, whose battlecry can be doubled after getting the quest reward to get even more of the combo pieces. On another note, while I think it's a really bad idea, you can potentially cut every card that costs two or less except for Fire Plume Harbingers, then your Witchwood Pipers can Tudor the Zola (after the Fire Plume Harbingers get tudored by the Sand Binders), and then you basically have tudors for the whole combo. But if it's worth it to run a overload spell package with Spirit of the Frog and Thunderhead instead of early game minions, I don't know. Just my thoughts, still needs to be tested when the expansion drops. 

The typical Shaman control Decks are Big, Jade, Shudder with Doppel Gangster, NZoth, and none have enough cheap battlecry minions to complete the quest and at the same time drawing the combo pieces. I think we need to make a different Shell. 

Is the OTK the only win condition? What decks do we want to beat? Do we want to be resilient vs anti-combo cards? Dirty Rat will be able to ruin our day, so should we be able to win with only part of the pieces? I think if the core cards have synergy with the rest of deck outside the OTK, then we will have a robust deck with multiple win conditions.

Since we are using a quest, we need to be able to reclaim the board since we are lagging behind on the board. Thunderhead is a good option as you suggested. We don't need to add much value besides card draw, because when the Hero Power comes online, it will provide value with our battlecry cards. Also, we do not want to clog our hands. Elemental based deck has synergy with the OTK pieces, and can win games on their own. An elemental/overload synergy based deck? 

Actually completing the quest should not be that difficult. Shaman is one of two classes that were stated by developers to have more lackey synergy this expansion (the other being Warlock). Shaman currently has access to three lackey generators, Sludge Slurper, EVIL Cable Rat, and EVIL Totem That's 6 total early game things that give you battlecries for the quest, 4 of which have battlecries themselves. How to stay alive is another story. TBH, I dunno. I mainly play standard, but I love these combos.

Also, to synergize with the lackeys and for early game pressure/removal, you can run Weaponized Wasp

Yes, completing the quest is not going to be difficult, and I agree that lackeys are the way to go. It is a departure from control type of deck which you originally suggested. Which is why I suggested going a midrange route.

Weaponized Wasp is a very strong card, which I want to include too. I am trying to avoid spreading too thin, because the last thing a Midrange Shaman need, are dead draws. Fire Plume Harbinger will be a useless card outside the combo, if the deck has almost no elementals. I am leaning towards a minion heavy deck, which means that Thunderhead may not fit the deck. So many options! 

As an outside combo, two Weaponized Wasps with any lackey and the quest reward is just 12 damage outright. Maybe there's a world where Barista Lynchen is used to get more Weaponized Wasps and/or the 2 damage lackey for just a burst combo with those. This could also be used as a sub-combo if the main combo doesn't line up well.