This deck's primary objective is to flip hadana's climb as early as possible. The best creature to give pre-combat +1/+1 counters to would be predator ooze, who becomes a 3/3  just from being turned sideways. With two individual triggers on the stack, he would be a 5/5 if you have hardened scales and become a 9/9 in your next combat step. Tap 3 mana and your winged temple of orazca to make him an 18/9 in the air. Flying green nose boogers.

Another great creature to give flying to would be the treacherous pit dweller. A slitherhead getting evolutioned into predator ooze so you can exile the slitherhead to put a +1/+1 counter on Treacherous pit-dweller before it's removed. With a hardened scales you need only to attack and your Demon becomes an 8/7. There are several paths to victory depending on what's in your opening hand. 

Treacherous pit-dweller

hardened scales

slitherhead

eldritch evolution

birds of paradise

overgrown tomb

botanical sanctum

This hand has two attractive plays you can make, only one of them will come to pass, depending on your opponent's ability to manage his or her early-game resources

A turn one birds of paradise followed by a turn 2 eldritch evolution finds your predator ooze. Unfortunately, your opponent topdecked path to exile and your ooze is gone as quickly as it appeared. (If your opponent wants to wait until you've revealed more information about your strategy, you may be lucky enough to topdeck a spell snare.) Now search for a forest, you've got more to give.

Assuming you drew a land, you'll be doing well with 4 mana sources thanks to PtE. A small mana-dvantage is all this deck asks for. Spell snare is going to stop a vapor snag or a path to exile from snuffing out your 18/9 flying indestructible oozeball. Sideboard is filled with hard removal and some fog effects to buy some time against 8 whack. Abrupt decay stops affinity, LotV, blood moon, just about anything really. Several key cards sit at the 3cmc mark so Dimir machinations helps you grab hadana's climb. Don't fetch for predator ooze since you can already find one using either CoCo or eldritch evolution. Golgari charm  stops lingering souls and blood moon, slaughter pact is a sweet pickup with dark confidant but you've still got fatal pushes if the problem is death's shadow (which can be spell snared), and unless you're behind, you'll win that race with a little luck.