@Rn1 no worries each of them basically have two name, if more than that might be based on their victory and named. For example (can be understand like the front name showing is their full name, and the second name is their nickname) Wei Wu Xian - Wei Ying Lan Wa** Ji - Lan Zhan ; Han Guang-kun (for some reason i doesn't know about the junior calling Lan Zhan as Han Guang-kun)
@christine leong Han Guang Jun is basically a form or respect to their senior in the Gusu lan sect and other sect for example Sect Leader Jiang, And uhh I forgot what they called Lan Zhan's brother but yeah it's basically that a form of respect name
@Rn1 Name - Nick Name(Only for close ones) - Title Wei Wuxian - Wei Ying - Yilling Patriarch Lan Wangji - Lan Zhan - Hanguan Jun Jiang Cheng - Jiang Wanyin - Sect Leader Jiang Lan Xichen - Lan Huan - Zewu Jun