Please don’t steal other people’s work and try to redistribute it, especially if you’re trying to sell it. You will be banned.
Viewing post in "Copyright" or "Transformative", "Fair Use"?
Maybe tone it down a bit. You claim to be ex military. Those types usually have more civil manners.
While this advice is not referencing to your question exactly, it is still the advice that counts. If whatever you plan to do will be considered stealing, do not do it. Now you only have to find out, if it is considered such or not. And you will not get any qualified legal advise in community. We are not lawyers here.
I did read the question, in your very post you admitted to taking other people’s work to resell:
If I were to take multiple screenshots of popular AAA 3D games (such as Call of Duty, Doom, Left 4 Dead etc), then manually cut-out the weapons (in GIMP/Photoshop), then manually re-trace them as “pixel-art”…
I don’t see how there is any ambiguity there. You’re looking for a way to take the work of others and change it “just enough” so that you won’t get caught. I think the intent is pretty clear here, and I can tell you now that it is against our terms and you will be suspended. I’m going to close this thread since there doesn’t appear to be any constructive discussion to be had here.
Thanks