normally to accomplish what you ask you can simply copy the color string from one object’s properties to the other
(e.g. Style , Background , More colors , in the brush editor , Color Picker)
I use to copy past this code on my projects…
I think there are other options like for example the possibility to work with “User Brushes”
You can create your brush and you will find it directly in the objects brush editor , if you have recurring custom colors I think it is a “clean” solution.