@Sassafraastree
I was afraid that might happen and I'm sorry that it didn't work.
Since you're using the Legacy version of the game, another thing it could be is if the new CC you can't see in game was made with a base object from a pack released after the switch that brought Legacy about. By object, I mean pretty much anything in the game, CAS or build/buy. Or even some of the base game or earlier pack objects where the objects were updated for the later packs and may be incompatible with the Legacy version now.
Just because a file will show up in the list at startup, doesn't mean that it will work in the game. If it has the package extension, it will show up in the list. That doesn't mean the game will actually read and load the file. If the game runs into a file it can't read or is otherwise incompatible when it's loading, it will simply skip the file and not load it. I know it will happen with broken items and I suspect it may be happening for you if the file is incompatible with Legacy.
And it could be a mod as well. I know that MCCC has a Legacy version. Some others do as well. If you happened to get a mod made for the regular version of the game rather than Legacy by mistake, even if the mod seems unrelated to CC, it could be the problem. It's worth checking just to make sure.
The only way to find out for sure is testing though if something will work with your version of the game or not.
Edit: One thing that I thought of is to check if you have to run the Legacy version. There have been other posts about Legacy where the helpers here have found that they didn't really need to and their computer was capable of running the regular game. So, if you would like to know that so you could switch to the regular game version, just run a dxdiag and attach the results to your next post. Here's how you do that. How to gather information on your PC using DxDiag (ea.com)
Hope this helps.