Getting a decent DOF is fine but if you have a flower with a dynamic color and a contrasting background you can use a smaller aperture and get a sharper image. The yellow on yellow wouldn't work but red flower on green could do the trick. What type of lens are you using, you seem to be focusing too close on some of these. I say based on the slightly out of focus image and the fact that most are cropped (first and last) too closely. I don't have a macro lens but I do have a macro setting on some of my cameras and one thing I noticed is that the camera won't autofocus within an inch of the subject.
Don't know what to make of #3 - Something is not quite right there, bu I just can't put my finger on it.....
I need more coffee!!!!!
That said, I like $ 2. Maybe brighten the white flowers a bit?