When Wu Ling considered the others, Zhang Buyan and his Junior Sister were invested in the furthest destination the group was aiming for. In the near term, he felt he could rely on them to be committed if cautious. Similarly, Su Xiang might question him but she would do it from a place of good intentions. That left Xiong Dahuo and Yu Jinqi as the most vulnerable elements that he should reinforce. Xiong Dahou might have become the disciple of his father's mistress, but their relationship was built on shaky ground at best.
Yu Jinqi, on the other hand, seemed to be as close to breaking through as Su Xiang was. If Wu Ling could figure out a way to help him make a breakthrough to Novice early in the journey, he was certain that not only would he gain a reliable supporter within the group, but the group would then gain the benefits of an Alchemy Novice for the rest of their journey.