Input field with icon and placeholder as label

I was prototyping some inputs for a product I plan to develop and was wondering about the bad practice issue envolving the use of placeholders as labels. My question is: with the use of an icon altogether, can I achieve a better result with better affordance? Can a icon, along with a placeholder, replace the label in the context of a form? I also made two others labeled examples (first one and last one) hopping that you guys could help me to understand which one would be better, keeping in mind that I seek cleaness on my design (not willing to lose affordance for that, though). Thanks