Conjurer's Closet is a must have for this deck. Allows you to blink Tazri to tutor each turn. Also, Xenograft will work well with Turntimber Ranger and some of your allies for infinite triggers.

You could use a few more five colour lands, like City of Brass, Mana Confluence, Reflecting Pool, and//or Gemstone Mine. Cavern of Souls is really good if you can get one, but at that price tag it's not really worth it ATM. Sylvan Library is my favourite card draw source in EDH, and worth it in every EDH with green for the draw power it gives. Join the Ranks is too slow to be really useful.

Look at my ally deck... it's not perfect, but you should think of putting some of those cards in there. One thing for sure: Add Rally the Ancestors

I'm trying to build a Tazri deck right now as well. I'm completely clueless about where to go with the non-creature spells, but I like the direction you're heading.

Flameshadow Conjuring is excellent in a deck like this.

Venser, the Sojourner, also a very good card to blink your Allies.

Harsh Mercy and In Garruk's Wake for removal.

Unified Front for tokens

Legion's Initiative also to blink.

Blade of Selves for Multiplayer.

Birthing Pod to fetch Allies and to trigger them.

Cloudstone Curio to blink the Allies.

Call to the Kindred free Ally each turn.

Conspiracy and Deadeye Navigator, with Conspiracy you are able to fetch every creature with general because every card in your library will be an Ally.

Vedalken Orrery to flash everything

Sun Titan, Angel of Finality, Clone Legion Agadeem Occultistand Adaptive Automaton might also be a choice.

~Cheers

I'd suggest some cost reducers to help lessen the mana load.

Cloud Key or Planar Gate would assist.

Forbidden Orchard and Exotic Orchard are great in 5 color decks.

Now that Eerie Interlude is EDH legal, you should run that instead of Ghostway, because you can avoid accidentally killing all of your tokens. Other than that, great!

I suggest putting these cards in there. These are ones that I have in my Ally deck, or as my friends call it, the less evil sliver type deck

Venser, the Sojourner -blink creatures in to kick off abilities, and can make them all unblockable for the knockout

Coat of Arms - a nice 5 drop artifact that will boost your creatures

Joiner Adept - a nice two drop creature that makes it so you can tap your lands for any mana

Clone Legion -good late game card that usually win the game

Conflux -a bit costly to play,8 drop, but searching your deck for 5 cards will he useful

All Sun's Dawn - 5 drop spell, for each color return up to one to your hand from your graveyard

Rite of Replication -pay its kicker on say Halimar Excavator will give you an would hurt the opposing player badly, or let you win if you got enough Ally creatures on the field

And I suggest getting something like Freed from the Real to attach that to Harabaz Druid, cuase if you have at least one other Ally on the field, infinity mana combo, and seeing how Tazri ability doesn't make you tap her, you can do it infinity times

You might want to add one or two extra board wipes. Sometimes the board state might not always be in your favor. Since your in 5 colors you can pick the one that best fits your budget.