The name Hua'an originated from her birthplace.
The place where her spirit was born was a birch forest.
It was dusk when she came into being, the white birches with black spots stood tall in the setting sun, their shadows stretching longer with the light, and it was during this transition from day to night that the Spirit Energy Field shifted, nurturing Hua'an's spirit from the natural world.
The reason why her last name is Gansong is that the Fairy who helped her with Enlightenment and shaping was named Gansong. Similarly, this Fairy named Gansong·Frozen Fish was also born in a land abundant with wild savory vegetables, hence her name Gansong·Frozen Fish.
And as for why this Fairy's surname is Frozen Fish… there's no need to explain that.
After all, the tradition of Fairy names and surnames follows this principle: the surname inherits from the Shaper of this life, while the given name reflects one's own characteristics.
