Student Council - link for reference
Cai Renxiang and her mother are either based on, or have massive similarities, with the antagonists of Kill La Kill. By coincidence, Ling Qi shares marked similarity to another one of the antagonists, Nonon, and Gan Guanli seems to share a lot of qualities with Ira. So, its a running joke that CRX's Retainers are going to get two new members that resemble the remaining two antagonists from the anime.
Nonon is tiny and pink though. Ling Qi is taller than unbuffed Gan some of the time(probably not forever)
As for the vote, what we've seen is that:
-Hanyi is central to the negotiation. Engaging her is relevant to the journey plot arc.
-Xia Lin is notably jumpy and reacts martially to spirits first. This isn't a problem
yet, but a more powerful spirit or worse, a diplomatic party seeing your party member reaching for a weapon upon sensing them may react poorly.
-Xia Lin is visibly immersed in the Celestial Peaks modes of thought. She expresses difficulty in talking about Cui as a person. This is important, her pokerface equipment actively hurts her here - people who can't magically divine your intentions are going to go by your behavior, and she's going to be flagging as "well, you're not exactly people" which is um...undiplomatic, even from the security.
On the flip side, Ling Qi and Zhengui are very...unusual environments to fight in. Combat efficiency will be degraded if people who don't know how to react to being in frozen burning mist and ash while stacks of walls explode from the ground are around. Its not a fatal problem, certainly Zhengui worked fine at the village defense mission without prior experiences, but they could be better.
So:
[X] Hanyi, whose nature was a key to the mission. (Increase group social cohesion)
Because this group has a lot of kill, even if they don't work together perfectly, but botching diplomacy for a preventable misstep is undesirable.