[McAroni]

For Point 2 and 3:

You could save every preset for your pen or other Tool in the favourites. After setting up your pen Go to the Star ar the top panel and press the plus Icon. 
You could set up a white pen there too..
You will have access to your saved favourites there, or through the command Bar. (the Symbol next to the layers panel)
And the switching is really easy. I have there multiple colors and also one white pen too...