As Jacky said, you can create a material and set it to Unlit for the mangos if you want to keep them 3D, which will work without any lights in the scene. You can still fake a light in the scene if desired by setting the light direction as a material parameter and doing fake lighting in the material itself on the materials you use for 3D objects.
I like the watercolor aesthetic you’ve got going; looking forward to seeing your progress 
Cheers,
Michael Noland