Many thanks @sarahlenker ! This is a great starting point for me as I’m still new at Unreal shader nodes. It looks promising for the effect I’m looking for; I’ll experiment with these options!
I also saw a vid about “toon shader” looks in Unreal that may give more control over shadow colors but it’s another thing I need to experiment with. Thanks again for the ideas!
@Only-Preston and @RobertoCosta_Dev thanks for the comments. I was researching this topic after I posted the question and found a possible way to do custom color shadows by doing Shadow Catcher/Shadow Pass renders and adjusting isolated colors in an external post/compositor program. I’d prefer to do it in Unreal but I’m okay with doing it outside of Unreal.