In LCH, Guo Jing, is from Niu Village at Northern China, which is I remember their parent speak dialect (forget what it is), and his mother once say she missed speaking dialect with his father (Guo Xiaotian and Li Ping).
I remember only in XAJH that JY put some dialect situation where the Yu Canghai is using Sichuan dialect.
Can list again wuxia character and their dialect / Han etchnic known in JY or GL novel ? For non Han I think quite obvious like Xiao Feng is Qidan, Zhao Min is Minmin Teimour and Mongolian etc.