Change uniform of NPC's in Sims 4 Studio?

Not sure if you still need help on this, but I think so... outfits for these service sims seem to be defined inside of their Situation Job Tunings. So, maids' uniform info is in the "job_maid" tuning (16174). There's a TunableVariant named "job_uniform" in there that I think you could copy and paste to the Situation Job Tuning for your new event NPC/Guest jobs to make them use the maid outfit:

<V n="job_uniform" t="uniform_specified">
<U n="uniform_specified">
<E n="outfit_change_priority">Medium</E>
<E n="outfit_change_reason">Situation</E>
<V n="situation_outfit_generators" t="enabled">
<L n="enabled">
<U>
<T n="generator">159505<!--outfit_Uniform_Maid--></T>
</U>
</L>
</V>
</U>
</V>
As for how to actually make a custom outfit snippet... I'm not entirely sure. It looks like these outfit snippets work by providing a tag from an enumerated list that is defined... somewhere?

<?xml version="1.0" encoding="utf-8"?>
<I c="Outfit" i="snippet" m="snippets" n="outfit_Uniform_Maid" s="159505">
<U n="value">
<L n="body_type_chance_overrides">...(mostly irrelevant stuff)...</L>
<L n="tags">
<E>Uniform_Maid</E>
</L>
</U>
</I>
I extracted the maid outfit from CAS (as override) to see if it had the "Uniform_Maid" tag in its CASPartResource thing, and it looks like it does. So if you wanted to replace a pre-existing situation outfit, you might extract both the item you want to replace and the one you want to replace with with CAS as a start, and swap the tags that are used for the situation outfit snippet between the items. I'm not 100% sure this will work, but it's a start, I guess.

I couldn't figure out where the actual enum of uniform outfit tags is defined, though, so if you wanted to add a whole new type of situation outfit I haven't the faintest where you'd start. If anyone else knows, I'd be curious to find out, too. (May be a scripting thing, but I can't really be sure)