I can see a lot of possibilities with either choice.
[ ] Lao Keung, the stolid soldier(opens the characters participation in various actions)
-jock time with three martial experts (Gan Guangli, Xia Lin) seems funny fun
-more professionally suited to the kind of initial security operations that are a priority during this phase of fief development
-better pick for possibly opening Bai-Meng dialogue with Meng Dan on past grievances
-witnessing the more casual/trust-based leadership relationship in play in Renxiang's group dynamic first hand helps prepare him for Meizhen's needs
[ ] Xia Anxi, the prickly diplomat(Opens characters participation in various actions)
-soft scholar/artist boy complaining about the cold, undeveloped frontier seems funny
-astronomy expertise may be applicable to starspawn, at least vaguely
-more directly, eases opening astronomy talks with that older guy and possibly Gan Guangli
-being out in the sticks at our mercy away from Meizhen potentially opens him up for some shell-cracking so we can meddle with the soft gooey insides of his psyche
[X] Lao Keung, the stolid soldier(opens the characters participation in various actions)
Going with this because soldier time amuses me. Also think Lao Keung's philosophy might serve as a useful counterbalance for exploring Xia Lin's, which is still somewhat unexplored. There remains an undercurrent of tension between Xia Ling and Cai Renxiang but not a lot of opportunities to poke at it. The role of heritage and identity in Lao Keung's/Red Caste's martial philosophy is particularly interesting in contrast to Xia Lin's clan in general and martial service under the Heron General Xia Ren in particular being an exercise in refuting ancestral cultural heritage.
There's some really cool push and pull the two of them, Xia Lin and Lao Keung, could have with each other there. Balancing the individual and the cultural group and where meaning and purpose arises/can be justified to exist and such and so on.
Who knows, they might even make a cute couple.