In Joy of Life, the person Si Lili met with Fan Xian was Lin Gong. Lin Gong was Lin Wan 'er's second brother and the son of the Prime Minister. Si Lili told Fan Xian that Lin Gong was a spy from Northern Qi. He was the mastermind behind the Niulan Street assassination. Fan Xian learned the truth from Si Lili.

Si Lili met with Xiao En, the spy from Northern Qi. In the original story of Joy of Life, Xiao En was Ku He's disciple. Back then, he and Ku He had met the temple in the desert. The two of them had found the secret manual that Ye Qingmei had left behind for their descendants in the temple. Ku He returned to Beiqi after he finished his studies and became a Great Grandmaster of Beiqi. Xiao En had been searching for Ye Qingmei's son. He wanted to tell the Emperor of the time about this so that he could gain more power. In the TV series, Si Lili was a spy from Northern Qi. She and Xiao En went to the temple and found the key Ye Qingmei had left for Fan Xian. After Si Lili and Xiao En returned to Northern Qi, they told the Northern Qi Emperor, Zhan Doudou, the news. In order to obtain the secrets of the Temple, Zhan Doudou decided to let Si Lili get close to Fan Xian and obtain information from him.
In Joy of Life, the person Si Lili met with Fan Xian was Lin Gong. Lin Gong was Lin Wan 'er's second brother and the son of the Prime Minister. Si Lili told Fan Xian that Lin Gong was a spy from Northern Qi. He was the mastermind behind the Niulan Street assassination. Fan Xian learned the truth from Si Lili.
In Joy of Life, the person Si Lili met with Fan Xian was Lin Gong. Lin Gong was Lin Wan 'er's second brother and the son of the Prime Minister. Si Lili told Fan Xian that Lin Gong was a spy from Northern Qi. He was the mastermind behind the Niulan Street assassination. Fan Xian learned the truth from Si Lili.
In Joy of Life, there was no explicit mention of Si Lili meeting Fan Xian. Therefore, based on the information provided, I don't know who Si Lili met in Joy of Life.
During the Qing years, the person Si Lili met with Fan Xian was Lin Gong. Lin Gong was Lin Wan 'er's second brother and the son of the Prime Minister. Si Lili told Fan Xian that Lin Gong was a spy from Northern Qi. He was the mastermind behind the Niulan Street assassination. Fan Xian learned the truth from Si Lili.
In Joy of Life, the person Si Lili and Fan Xian met was Lin Gong. Lin Gong was Lin Wan 'er's second brother and the son of the Prime Minister. Si Lili told Fan Xian that Lin Gong was a spy from Northern Qi. He was the mastermind behind the Niulan Street assassination. Fan Xian learned the truth from Si Lili.
In Joy of Life, Si Lili met Fan Xian. In the first document, it was mentioned that Fan Xian and Si Lili had met in prison after Fan Xian was assassinated. In addition, Fan Xian often met Si Lili in her carriage. However, the details of the meeting and the content of the conversation were not provided. Thus, they could confirm that Si Lili and Fan Xian had met, but they could not provide more detailed information.
In Joy of Life, the person Si Lili met with Fan Xian was Lin Gong. Lin Gong was Lin Wan 'er's second brother and the son of the Prime Minister. Si Lili told Fan Xian that Lin Gong was a spy from Northern Qi. He was the mastermind behind the Niulan Street assassination. Fan Xian finally learned the truth from Si Lili. Therefore, Si Lili met Lin Gong in Joy of Life.
In " Celebrating Years," the person Si Lili and Fan Xian met was Lin Gong.