Question - Way To Make Downloaded Sim Not an Occult?

Unfortunately, no, there is no way to turn an occult sim back to non-occult sim through CAS.

You have two ways here. I'd make a separate save to cure her and then do one of the following:

• Wolf-Be-Gone potion: This potion can be made to cure werewolves. You can either try to find it in the Gallery (though I don't know exactly if it'll be possible through there). Or, have another werewolf learn the Lunar Epiphany ability through reading werewolf books, then read more to learn the potion, then collect the required ingredients and make it through a bar. Then add her to the household (don't add her before, she may gain additional traits/skills/loot during that time) and have her drink it.
  
• Or... Cheats... Still...
  While she is selected, the cheats you must enter are these:
  

  testingcheats on

  
  And then:
  

  traits.remove_trait trait_OccultWerewolf

  
  And it'll remove the occult status. In addition, if you enable testing cheats in one save, it won't be enabled in other saves, thus this is why I suggested another save.

Whichever method (besides mods) you choose, good luck!

MCCC mod will let you do it with a few clicks, but you’d need the mod.

Thanks !NRowe! I do have MCCC installed already, so I'll try that first since I don't really want to go through all of the steps suggested by @EgonVM (but I do appreciate you taking the time to explain and write that all out for me!).

I was really just hoping it was more simple than it is or that I could clone her or something as a "blank" sim. I just like her looks, it fits my story, and I don't really care about her traits and stuff. (I'm just horrible at Sim creating, so I leave that up to the experts and download their glorious sims instead!)

If you have MCCC, place the Sim and then using MCCC centre directly on the target Sim go into the occults commands and somewhere very close in there is “humanise Sim”. Bam!