Assign specific options for a field

I want to let the user assign some options for a Category field, like icons and colors.

As example, I have a main form with a field named "Category", as a dynamic field pulling from another Categories form. Some of these categories are, let's say, Home, Work, Entertainment, Vacations. When the user choose one of them, an icon and color are pre-assigned to that cathegory, like Home (house icon, blue), Work (building icon, green), Entertainment (movie icon, red), Vacations (travel icon, yellow). The color would be related to the category, not to the icon.

But at some point, users would want to change those icons and colors, choosing from a given collection (and maybe add their custom icons, too) and a color picker to select any color they like, aside from a specific set of colors. What would be the correct approach to this? I thought about making a form for icons with File Load types and another form with predefined color codes (althought a color picker would be nice, too), then relating both fields to the Category form.

Any help?