Hua Cheng= 190cm, [19/20 y/o, chapter: 36], "Hua Cheng’s appearance this time around didn’t only seem to look a couple years older, but he’d also grown taller. Before, when Xie Lian looked at him, he could still manage to maintain the same level of eye contact, but now, he had to strain his neck to look up."➔Chapter:37

San Lang= 185cm [16/17 y/o, Chapter: 13], "Xie Lian finally looked up and realized with a start that San Lang was actually a head taller than him! It wasn’t obvious when the youth was lazily lying in the hay, but standing tall, the two couldn’t see eye to eye on even ground."➔Chapter:15

Wuming= perhaps also 185cm since he is the same age as San Lang. "That black-clad warrior rose to his feet, and when Xie Lian looked back, he discovered that this young man was actually much bigger than he had expected. Probably around sixteen or seventeen in age, but already enormous in size at this age, and even taller than him by a bit."➔Chapter:192

https://twitter.com/pheeebas/status/1155074737464201216?t=5BZDReslw2ofmNkXUESBug&s=19 maybe this will be helpful :)