For light sources, have you also planned to add setters to modify the color for example?

No, even if it's not declared as [font=courier new]final[/font], the [font=courier new]LightSource[/font] class like a few other model classes ([font=courier new]BackgroundImage[/font], [font=courier new]HomePrint[/font], [font=courier new]Baseboard[/font], [font=courier new]HomeMaterial[/font], [font=courier new]HomeTexture[/font], [font=courier new]Sash[/font], [font=courier new]TextStyle[/font]...) are immutable.
If you want to change the color of a light source, create a new [font=courier new]LightSource[/font] instance and call [font=courier new]setLightSources[/font] on a [font=courier new]HomeLight[/font] instance.