the biggest factor i think about when you say soundplay is what allows him to win, is trying the same and seeing just how loud i have to make my speakers to even hear a "twig breaking" from the host, for example in the town replay when hes hanging behind the building at mid or in the garden replay when he was staring at bow and rebar dying.
Speakers? What if he is using headphones? Other games require heavy sound-play where you need to know where the enemy is. I was listening through headphones and I can hear which direction the RL and SG spam were coming from. And I don't need to raise my volume too loud.

If i was him i would find it unbearable to play with such a high volume to hear especially if there would be a player macro taunting for a second and ill go deaf, or any player dashing nearby to me. This is why I dont think many of the moments you consider soundplay to be so, and i hope you can review that with my thoughts in mind.
If you /ignore the player, you will not hear their taunts.

Overall, the big advantage he had was the constant lunge that he was able to produce which allowed him more travel time to get one place to the other. The way he positions himself especially in town was where one direction where he can see and another direction so he can listen (Most times where he can listen was where a lot of people were located).

From watching the replays, I believe he's not ESPing but just experienced with sound play, using knowledge of teammate's death as an advantage.