Are Song and Xiao Luanzi acting alone?

No, according to the plot of The Legendary Shopkeeper, Song is the Song in The Legendary Shopkeeper, played by Chloe Wang, and the son is played by Gu Zhixin, not himself. The Legend of the Boss is a legendary drama directed by Danian Tang and starring Gu Zhixin, He Bing, Yang Lixin, Guanhua Liang and Yuan Yu.