I mean, Houken irl was a very wise and generally anti-war man who wasn't known for exceptional skill-at-arms, Heki is supposed to be dead by this point, and Li Xin came from a well-to-do feudal family so...Hara has a good amount of leeway to fuck around if he wants them to have kids or whatever. Yuan Duanhe, Wang Qi, and Huan Yi (Yontanwa, Ouki, and Kanki) are basically nobodies in the Records of the Grand Historian but they got major overhauls and roles in the manga. Qiang Lei's sex also isn't ever explicitly named in the Records which probably means it's a man (since they'd mention it if the general had tits) but heyKyou Kai was inspired by General Qiang Lei, who in real life was a man. I think it's very unlikely that she and Shin would have a child.
Historically, Qiang Lei more or less disappears after the fall of Zhao, specifically after Li Xin (Ri Shin) captures Handan (Kantan) on the orders of Wang Jian (Ousen); it's not said that Qiang Lei dies or anything like that, but no more is ever heard of him, which probably means he either got sick and died after retiring/sustaining an injury or that he never had any more independent actions that resulted in anything worth noting. It's extremely easy to spin that as Kyokai getting herself widened by big Shin chinpo.
We don't know anything about Li Xin's wife, but he definitely had one since he had one famous kid (Li Chao) and Li Guang, Han's "Flying General", is also descended from Li Xin (which also makes Li Xin a direct patrilineal ancestor to the Tang emperors, go figure). That means it's actually feasible for Qiang Lei to get crippled in the Zhao wars and become a homemaker.
We don't know anything about Li Xin's wife, but he definitely had one since he had one famous kid (Li Chao) and Li Guang, Han's "Flying General", is also descended from Li Xin (which also makes Li Xin a direct patrilineal ancestor to the Tang emperors, go figure). That means it's actually feasible for Qiang Lei to get crippled in the Zhao wars and become a homemaker.