Little Celestial Master Wen Ji's surname was Tang. She was the youngest daughter of Tang Wangsun, the Lineage Celestial Master of Azure Mountain.
When others mentioned Azure Mountain, they called it the Green Mountain Sect or something similar, but Azure Mountain's main branch had never considered itself a sect.
Azure Mountain was not a sect. It was the legitimate lineage of the Shangqing Tradition. Other schools could call themselves branches of the Shangqing Tradition, but Azure Mountain considered itself the orthodox tradition.
Thus, they called themselves the Azure Mountain Lineage. Its highest-ranking leader was known as the Lineage Master, with the honorific Lineage Celestial Master.
When outsiders spoke of the Azure Mountain Little Celestial Master, they were referring to the Lineage Celestial Master.
Who was the Grand Celestial Master? There really wasn't one. But without the word "Grand," there was indeed a Celestial Master—the Celestial Master Zhang of Jiaohuang Mountain.
Azure Mountain looked down greatly upon Jiaohuang Mountain's Daoist lineage. However, Jiaohuang Mountain had received Imperial Court recognition, something Azure Mountain could not compare with. And it was not merely one person who had been invested—the Celestial Masters of every generation had borne the surname Zhang.
Jiaohuang Mountain's lineage was essentially a hereditary temple, while the Azure Mountain Lineage could be classified under the Ten Directions Monastery. Of course, Azure Mountain also passed its teachings from master to disciple, but broadly speaking, Azure Mountain's Lineage Celestial Master did not come from one fixed surname.
That was enough digression. In short, the Azure Mountain Little Celestial Master Feng Jun and Zhuang Haoyun had mentioned was Tang Wangsun. As for why "Little" was added—if Azure Mountain objected, it could take that up with Jiaohuang Mountain's Celestial Master Zhang.
In any case, that was what everyone thought. No matter how legitimate Azure Mountain's