Pretty certain if you are going to be changing class names, the Sharpshooter or Spitfire class would be far, far closer to the concept of a Gunslinger than the Launcher. Not to mention, though there are some slinging and acrobatic techniques with the Launcher, the class is slow because of the big weapon, which completely defeats the purpose of a Gunslinger archetype. Looking at the manhua RAWs, Google Translate does say Gunner, which I have a feeling is referring to one of the six main classes.
Unfortunately, I'm too lazy to I decided to go to the source on Qidian for the webnovel, as well as cross-reference from the anime, and found something quite interesting: in the webnovel, Butterfly Blue used the term 枪手系, which threw both me and my friend (who is from Hong Kong; I'm not, I just dabble in the language), which is a bit different from both the manhua here, as well as the anime, which uses the same characters in the manhua (枪炮师). After talking with him, I can def see now how the translator would get "Gunslinger" out of 枪炮师, though, so I can't really blame anyone for not knowing if they haven't read the source material and/or watched the anime.
But yeah, "Joyful Flourish Internet Cafe" is indeed quite interesting, as 兴欣网络会所 officially is Happy Internet Cafe, though the first character xing does make me question the veracity of the official translation on Webnovel. Then again...for some reason the series is called "The King's Avatar" when Quan Zhi Gao Shou literally means "Full Time Master/Expert", so ¯\_(ツ)_/¯ I'm very curious as to how ya got Joyful Flourish Internet Cafe, as that does sound quite awesome. Though that does kinda defeat the purpose when the cafe's name gets made fun of quite a few times throughout the series. xD