Should a character have lighting inside it, or around it, to illuminate the character? I'm working with a CC3 base in Unity. Thanks.

I'd use a Sub-Surface Scattering Shader on the Skin. Unity Asset store has some good and affordable ones. 
Domaginarium's is good - https://assetstore.unity.com/packages/vfx/shaders/domaginarium-s-sss-skin-shader-34487

As is Ciconia's (they also make a simple 2 side Hair Shader that works well) - https://assetstore.unity.com/packages/vfx/shaders/skin-shader-67724

These will allow translucency on the skin, letting it interract with external light more naturally, and give a slight lit-from-within look

Sounds great, thanks for the help.