Another thing you can do to compensate for the inconsistency introduced by having two tribes is to run more cheap card draw. Stuff like Night's Whisper and Read the Bones can really help shore up sketchy hands full of minotaurs and goblin lords, for example. Drawing more cards is a slight nonbo with Neheb since he wants you to have one or none in hand, but extra cards are so good.
Cashing in on multiple tribal synergies simultaneously is difficult, but possible. Changelings help a lot. I usually go way into the garbage heap for my cards, but there are a few reasonable changelings: Skeletal Changeling because it can chump block, Moonglove Changeling because it only has to threaten to block (also very good with first strike), and Taurean Mauler because it's a reasonable card on its own aside from being a goblin/minotaur. Having even one changeling in your deck also means that Goblin Matron, which you were probably playing on the goblin side already, can fetch up a minotaur. Along similar lines, Mutavault and Runed Stalactite help to tie the two tribes together.
Tombstone Stairwell can generate an enormous amount of triggers of Blood Artist and the wardens. Also, and sorry if this comes off as pedantic or nit-picky, but the creatures you listed don't generally trigger when a creature leaves the battlefield; just when one dies. The distinction is actually pretty significant since there are tons of blink and flicker shenanigans to be had in WB that don't trigger your Zulaport Cutthroats.
My original combo isn't refuted by Izzet Guildmage because Turnabout costs 4. But yeah, Reiterate does kill it. Reset basically can't get involved because then Izzet Guildmage will most likely refute the resulting combo.
No good. Twinflame has to resolve for you to get any tokens so by the time token-Dualcaster Mage's triggered ability resolves, Twinflame is no longer on the stack. Also, Dualcaster Mage (in hand) + Twinflame is infinite tokens by its self. No Zada required.
Because I reread Bazaar of Wonders and saw that it bans spells with the same name as cards in graveyards and Spy Kit can't change the name of creatures in the graveyard. However, looking at it yet again, I now see that it says "...in play or in any graveyard." and so it does work with Spy Kit after all. Thank you for pointing this out. Reading is hard...
...Picture this - you cast the Expertise, people remove the Patron in response. Oh no! But wait! What if the Patron is active? Then you tap him and get a boatload of mana going, probably enough to just replay the Patron immediately. Expertise "whiffs" (you still get the free spell cast, mind you), but you're not too far behind and you baited a removal spell...
If only you had a snake in play to offer up you could flash the Patron back into play before the expertise resolves.
...today I was thinking about good ol' Inferno Titan. It can be resonated, Mirrorweaved, sneak attacked, unblockabled, and vanished into memory (build your own Blue Sun) to pretty good effect, and also points for hitting Swans and Rectors, so it checks all my desired synergy boxes, but it feels so darn tame.
The way your deck is configured, with March of the Machines and Opalescence, it can also mow down miscellaneous artifacts and enchantments. It's a testament to how insane this deck is that "Mirrorweave my Inferno Titan" is considered a tame play.
Edit: What do you think of Amonkhet? There's a pair of cards that just seem generically powerful in any Zedruu deck: Cast Out and Trial of Knowledge.
Flashhulk onto the battlefield, don't pay 2GG, let it die and search up the feeder and the guide. Trigger the guide to get back the hulk, sac hulk to feeder, fetch up Kiki-Jiki. Tap the goblin to copy the guide, sacrificing Kiki-Jiki in response to its own ability. Allow the clone ability to resolve, use your copied guide to get back Kiki-Jiki and repeat as needed.
Edit: What do you think of Amonkhet? There's a pair of cards that just seem generically powerful in any Zedruu deck: Cast Out and Trial of Knowledge.
In Hand: Protean Hulk, Flash
In Library: Carrion Feeder, Kiki-Jiki, Mirror Breaker, Karmic Guide
Flash hulk onto the battlefield, don't pay 2GG, let it die and search up the feeder and the guide. Trigger the guide to get back the hulk, sac hulk to feeder, fetch up Kiki-Jiki. Tap the goblin to copy the guide, sacrificing Kiki-Jiki in response to its own ability. Allow the clone ability to resolve, use your copied guide to get back Kiki-Jiki and repeat as needed.