The substitute setter of Chinese NT is Sun Yan born in 2001. Ni Fei-fan and she also participated in 2019 U20 WCH in Mexico the same as the winner, Japanese U20 NT. Ni Fei-fan didn't play well in this match even worse than in Final 6 of VNL 2019. I doubt her pressure was so much. The subsitute libero, No.18, Wang Wei-yi, is the same age as Wang Meng-jie and also as the third libero of Team A in 2017.
I give the roster of China Team B in 2018 AVC Cup and in 2019 ACH:
I feel the players in 2018 AVC Cup are better. However...
2018 AVC Cup:
S - Sun Hai-ping [now weaker than herself in 2018], Chen Xin-tong
OP - Wang Mei-yi [fracture in the warm-up this year], Chen Pei-yan
OH - Liu Yan-han, Zhang Yi-chan, Duan Fang, Che Wen-han [U20, the opposite of Wang Yi-zhu], Ren Kai-yi
MB - Yang Zhou [retired due to heavy injury], Zheng Yi-xin, Gao Yi
L - Meng Zi-xuan [much weaker than herself in 2018 and the same situation as Chen Zhan in 2014 WCH -full of afraid ], Gong Mei-zi
S - Diao Lin-yu [heavily injured now], Sun Yan [the main setter of U20 NT]
OP - Du Qing-qing
OH - Liu Yan-han, Zhang Yi-chan, Duan Fang, Wang Yi-zhu, Jin Ye, Zhong Hui
MB - Yang Han-yu, Zheng Yi-xin, Gao Yi
L - Ni Fei-fan, Wang Wei-yi