Regarding the sun... Make the sun (the center) a little smaller.... #4 has a simpler, smaller look with less colors.
#16 has a nice looking orange on the outside and yellow on the inside. Also, have another look at the sun that I uploaded as one of the reference pictures. (sun1.png). That one has a lot of character. We like a smaller sun center and a little longer sun flares (than you currently have it) that go around it.
Regarding the flower.... maybe a pink color is best... maybe red, maybe purple... check out the other flowers that the others have done... Thanks!!