Is Simic Ascendancy triggered by Awakening of Vitu-Ghazi?
The two actions (adding counters and the permanent type change) are two different steps of the same spell. That means they're executed separately:


  608.2c The controller of the spell or ability follows its instructions in the order written.


There's no rule prohibiting +1/+1 counters on a non-creature permanent. For example, the land Llanowar Reborn enters the battlefield with a +1/+1 counter.

So unfortunately Simic Ascendancy wouldn't trigger, as the counters are put on the land while it's not a creature yet.

Simic Ascendancy would trigger if the land was already also a creature prior to the spell resolving: for example, casting Awakening a second time on the same animated land, or casting it on a land that was animated by Nissa, Who Shakes the World.