@ladyxixi2000 Delphy's Dashboard misses a lot of conflicts and can flag some that aren't true conflicts. It's a helpful first step in finding problems but isn't reliable enough to be the only tool you use. There's no substitute for testing yourself.
Still, if you want to redownload it, this is the source:
https://modthesims.info/d/387006/sims-3-dashboard-tool-updated-1st-july-2022-v1-3-8217-25892.html
It's also very possible that a file was corrupted and isn't working in-game for one reason or another. Third-party tools aren't necessarily going to catch that either.
For the female sim, does a different skin work on her? Does this skin work on a different female sim in the same age stage? If you're over it, that's fine, but if you want to try once more, I'd suggest changing her skin, saving/quitting/reloading, and trying the original skin again, that is if it works on other female sims.
For the .sim files, you don't need to install them through the launcher. Just drop them into SavedSims, or create that folder if it doesn't already exist.
In the future, I'd suggest testing every new cc item in a clean user folder first, making sure it works on the sims it should and that it doesn't show up for or corrupt other sims. That way, you can identify problems before they get anywhere near your main saves.
As for OneDrive, if you set up Windows with no internet connection, you should be able to skip linking your Microsoft account. Even if not, linking one device should have no effect on any other device that isn't also linked to that account. Even Windows can't sync settings across devices if those devices don't appear to be owned by the same person.
