I also tested through cheats whether painting level 10 or the expressionistic reward trait unlocks all emotional paintings regardless of mood.
The answer is: both do independently.
Which makes the expressionistic reward trait obsolete in my view. You can't receive the expressionistic trait without reaching level 10 after all.
My sims can paint emotional paintings and they do count toward the aspiration but when they are in a certain mood (ex. flirty), the option for that emotional painting (flirty painting) shows up but is not highlighted with a color (pink). This is true of all the emotional paintings except when inspired. That does highlight the options with blue.
My sims do not have the expressionistic trait yet. FYI: In the past when sims have that trait it just adds all the painting options to the list, nothing gets highlighted with color.
So my only issue is that I'm not seeing the color highlighting which makes it easier to see the emotional painting option when your sim is in the correct mood.
