@danceswithchaos I might be able to help. I play with vampire-spellcaster hybrids (created on purpose).
Here's what you need to know:
The vampire and spellcaster states are both from hidden traits that you can add or remove using cheats. You have to enter the "testingcheats on" cheat before using any of these. I recommend backing up your game and/or saving your sim to your library first, just in case.
For vampires:
traits.equip_trait trait_OccultVampire
traits.remove_trait trait_OccultVampire
For spellcasters:
traits.equip_trait trait_Occult_WitchOccult
traits.remove_trait trait_Occult_WitchOccult
What you do depends on what you want.
Option 1) If you want your sim to just be a spellcaster and not be a vampire, you should be able to remove the vampire trait using the "Remove" cheat for vampires.
Option 2) If you want to keep the hybrid, but give your sim the sun resistance perk, you'll need to temporarily remove the spellcaster trait using the "remove" cheat for "WitchOccult". This will make your sim be just a vampire, and you will be able to access the vampire perks panel. Make whatever changes you want there. When you are done, use the "equip" cheat for "WitchOccult" to make the sim back into a vampire-spellcaster hybrid. You should not lose any spellcaster progress. All learned spells, levels, and perks will still be there.
Caveat: Since I have only done this from the direction of creating a hybrid on purpose (starting with a vampire that I added the spellcaster trait to) I am not 100% certain that "natural" hybrids born in game work the same way. I've heard they can be glitchy. Which is why I recommend making a backup first before trying it out. But these cheats do work for me when doing what I do. And progress for spellcasters is not lost when I remove the trait and then re-equip it.
