Progressing on the vector shapes. They will be filled with either a solid color, a gradient or a texture. Below is an image made with gradients only.
The gradient in the sun is being edited. Radial gradients can have focal point. Here it is on the top-left of the shape (the little arrow). The big arrow is the main radius (or ending radius).
The gradient of the rainbow is a radial gradient as well but interpolated on the corrected HSL colorspace.