There is a significant amount of misinformation in your post.
SCP licensing is not iffy or complicated: it is clean and clear. Please ensure that you do your research before replying. The matter of licensing is off-topic and another entity’s licensing concerns or otherwise legal matters are not something you should be involving yourself with.
The content of the SCP Wiki is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported license, which allows even for commercial remixing of material provided that you attribute the originals and release your content under the same license should you create a deviation of a work from there (the ShareAlike part). Furthermore, the SCP Wiki’s Licensing Guide has more information dumbed down. One of their sections explicitly contains a sales header.
So What Can You Do?, The Long Version, Paragraph 3:
Sell : You can sell the remixes you make based on the SCP Foundation. However, keep in mind that you probably will not get rich off of them, because under Share-Alike, anyone can freely copy, use, or download your stuff, and you will have no legal recourse provided they also follow the terms of the license.
With respect to the Licensing Guide, there are a few explicit mentions with regards to content that are outlawed in terms of commercial usage because the likeness of the originals was not released under a CC or otherwise public-use license. SCP-173’s image and anything created in its likeness cannot be used or sold, however anything created in the likeness of the article’s content is fair game.
You are absolutely able to make money off of articles on the SCP Wiki so long as they are abiding by the terms and do not unpermissively use works not released under a license allowing remixes in their likeness. That also being said, if you do happen to do overstep the license (such as use a model in SCP-173’s image’s likeness), it wouldn’t just stop at a DMCA - a lawsuit could be involved as well.
Roblox DOES NOT assume that you do not have permission to use IP, they assume the opposite. Moderation takes action only when an IP holder explicitly puts in a request for their works not to be used or for certain works to be taken down from the site. I don’t believe you have a citation for SCP games being taken down for licensing concerns either: if so, it’d be great to provide one.
Groups and small games “get away” with monetisation of SCP works because it is completely allowed. The SCP Wiki is very aware that Roblox has content creators making SCP assets (they even have a Roblox account dedicated to Roblox matters, though it is inactive) and they have reached out before in cases where a serious settlement had to be made, otherwise they’ve had no issue with this happening. You can review previous cases of license settlements via the SCP Wiki admin site, 05command.
Once again: do your research before replying and do not spread misinformation.
cc @Pleixdes - The only thing you’re going to have trouble with is creating your own SCP-173 model, as well as any other model for an SCP where its image is not released under a share license. I do believe there was a word on SCP-111 and SCP-1926 but those articles have since been changed and are no longer included in the guide. For safety’s sake: the rule was that SCP-111’s image could not be used and nothing from SCP-1926 could be used, image or article.