The third trailer is almost surely from at least two other games. The level in the last trailer is largely from Arkham City and the containers seem to be from Borderlands. I assume then that this is an Unreal Engine game?
Although, honestly, reporting that a Chinese game has stolen assets is moot. Unless it is some large corporation consciously targetting the Western market, they always will have at least some.

Is it me or does it look like an Unreal Engine copy of Final Fantasy XIV?

Well, I'd hazard the guess that they either did not find a translator for the new stuff… Or it was the usual Chinese translation: around 99% Chinglish with 1% being a few correctly placed articles here and there.

Supposedly, WarCraft started as a Warhammer license game, although to my knowledge nobody at the Warhammer license owner (Games Workshop) ever heard of such a thing. Although Blizzard admitted in the past times that Warhammer as a game was a blatant DuneII/C&C1 rip-off, and considering all their other games are freely "borrowing" game design ideas from everywhere else, at least nobody was surprised there. But their entire WarCraft world is an obvious Warhammer clone with just enough changes in some art and names that it is not holding up in court as a copyright infringement. Pretty much every game they ever made follows this formula, you can trace back most of their stories and art style to known elements, and a large portion of them are openly taken by Warhammer and other Games Workshop stuff.

(Jesszus, ez a gépi fordítás. )

Considering you just described Half-Life 2 from 16 years ago—a single-player-only game that forced you to register and download a barely working client to be able to INSTALL the goddamn game, let alone play it—I think your argument is, I don't know, roughly a decade and a half late now. Especially since you post it on the first and biggest offender of that crime to this day, Steam's Valve platform, that has more exclusive and registration-mandated games than PlayStation.
(Although forcing the Steam client down to everyone's throats is still a minor crime compared to the skin gambling and popularising and inventing texture file lootboxes, yet nobody seems to remember that Valve started the entire lootbox gambling mess and actively does it to this very day.)

They are a small Polish publishing firm that has a ton of smaller subsidiaries. Actually, even these are their games:
https://steamhost.cn/app/559100/Phantom_Doctrine/
https://steamhost.cn/app/792300/The_Beast_Inside/
Apparently, they publish only the Simulators under their own name. I'd guess those are the "in-house" ones.

I doubt it is a scam. Warner Brothers acquired it perfectly legally, it just took them six years for some reason to decide to sell it again. Nothing peculiar about an old game appearing on Steam's upcoming list, Disney did the same thing when they suddenly decided to pop up with a ton of MS-DOS era games.
As for the abandonware download, they are rarely truly legal if someone holds the publishing rights, unless that entity itself posts the game on the internet (like EA and Rockstar did for a few games back then), but most people do not really care.

Tags are fully automated with no human interaction. The publishers can freely assign them, of course.

I am not saying the group will be pointless but that it is an uphill battle, so be prepared for small victories only. Tags can be removed from smaller games that are not too much in the limelight. Although trying to assign correct tags to small indie games with only "Indie" and "Simulation" on them is also a nice undertaking.

Tags are trickier since the entire user base can contribute and they tend to do so in larger numbers. Gods know how many times we tried to remove the "co-op" and "space" tags from Fallout New Vegas, a strictly single-player game, but they always came back. (Then again, Bethesda posted it as a leaderboard game, despite having no score system or any online component for any launcher to store any kind of competitive data.)