Before you start:

HINT NUMBERS represent how many towers / minions(even for Spider+Mage stacks) you're supposed to place. So pay attention to that. 

So, I've been using this build for farming Embermount Volcano @ NMHC difficulty for about 5-6 months now. Yeah, long time I know, should've posted it before, but couldn't get a video recorded and/or I was bored. Anyways without digressing too much. This build holds for at least 1 or 2 AFK chars. And works 100% fine on a full 4 player team. I've not failed in +1 AFK since about 60 something runs while using this build.
I use a EV as my primary DPS becasue of her ability to fly for extended periods of time. This helps a lot for the Pheonix Boss as you can tank the fireballs in air and retreat down to the Healing area on the bridge and keep your AFKs alive. Most importantly you can get up close and personal with the Pheonix, as you'll see in the video below.

-- Now about the build, its pretty straight forward -- the LTs will draw aggro from Ogres. Minions will do their things and Gas traps will keep Djinns at bay.
-- Aura Stack on Bridge is to get healed and keep Copters coming from east-side at bay.
-- Make sure to stay away from Harbingers(deadly new enemy type) while upgrading / repairing at all times and pay attention to you HP bar as well.
-- Since I don't care much about map completion timings, I take my sweet time to upgrade stuff in the 1st(initial) combat phase itself(don't up the buff-beams until the end). But you don't have to if you can/wish to upgrade later.
-- Ideally you should be able to upgrade everything by wave 13 or 14.
-- On Wave 15 I usally bring my DPS EV(1.75 Skin) and AFK Monk for boosting(if needed LOL!) or my Apprentice for a sure shot at getting an Ember Staff. 
-- Tackling the Boss is fairly straightforward as well -- I just fly into the Phoenix and since you can activate the Proton Blast in air and use it for a long time, it helps getting loads of fast damage on the Phoenix. If the 2 player HP(about 600M) is too much for you then just farm solo, its better.
-- My EV has about 104M DPS on her ProtonBlast in the Tavern, without boost. So adjust the boss timing accordingly. Also the Phoenix doesn't have a fixed path so often you'll have to improvise and time your flying + activing ProtonBlast accordingly.
-- In case you miss it, then make sure to at least re-fill it quickly with your stored mana or jump down and grab some(there's plenty of mana on the map).
-- Taking hits from the fire balls in air will make them ignite in-air itself, this can be helpful as you don't have to walk around on the bridge to dodge them and get some timely healing.
-- My EV Stats are -- 5740 Hero DMG, 5000 AB2, a 114k Ember Scptre with bad stats. a 190 Boost Prop Cat.
Video speed is at x1.5, so adjust the YouTube playing speed accordingly if case you can't figure out a build position.
 

Enjoy and good luck with the drops!
PS: If you want to maximize your EV DPS, then take a look at this guide made by Atherial here.