Of course I've been up all night! Not because of caffeine, it was insomnia. I couldn't stop thinking about coffee.
Say for instance I have two brushes in my studio. I have the ability to paint two yellows and a blue, with both brushes being on the yellow. If I take two cards from the lesson to add to my portrait (lets say one has double yellow and the other is blue), can I add the double yellow to my painting, then use the arrow ability from my starting tile to move a brush to the blue, then paint that?
Lutz is correct. To be explicit, what you describe here is not allowed because those brushes have been used already that round.