For colored pencil art, is it better to ink over your initial pencil outline, or just start coloring over your pencil outline? And if I just color over the outline, how can I avoid smudging the lighter colors?
Color pencil considered as a light to dark application, thus tracing your initial sketch with any dark medium will ruin it (they will be visible beneath your painting, unless you intentionally want to do so like mixed ones) . So in my opinion you definitely should not do that. Try to keep your pencil sketch as light as possible, barely can be seen. Then start with the lightest color / value and least pressure, continue by lying down darker tones gradually to build up the painting.
You should preserve the light from the white of the paper or cardboard and you always can go darker but using an eraser will disturb both your pencil marks and the surface texture.