HEAD CANON  
I imagine that post Sounds of Silence, diplomatic ties were opened between Equestria and the Kirins. Diplomatic groups would be sent from the Kirins and I imagine Autumn Blaze, playing an important role in returning their voices, would be a member of those parties.
 
At some point the Kirins would be free to explore Equestria at their leisure. Autumn Blaze, having lived in a forest for several years alone, wished to explore some of the major forests in Equestria. She chooses to wander through the White Tail Woods, which my own OC Autumn Science often trots through during the Autumn Season as it lies just west of her hometown of Withervale.
 
Now my Autumn is not a super amazing musical singer or anything, but she’s not bad. Upon hearing a pony’s voice in the woods, Autumn Blaze searches until she finds the pony. The Autumns meet, and become friends through a shared love of singing in an Autumn forest during the Autumn Equinox which begins the Autumn Season.
 
Artist’s Notes  
So I’d originally planned on finishing this in time for the official release of Sounds of Silence in the US back in September, but then my computer broke in the middle of it and I couldn’t finish in time. I don’t care if its winter now, I still wanted to finish this and kept it Autumn themed for the sake of full-filling the original idea.