I really love the look of the last one but worry about the stiffness, for all the reasons Jessikams said. I would also worry about stiff denim in the heat of my former climate (which is similar to yours, I think). I can see it as perfect for my current climate, so it might work well for you in parts of June and then September, would be my guess.
Here's the thing. Do you wear full length jeans at all in the summer? If not, then a long denim skirt will only be marginally cooler, and might not be breezy enough for your summer climate.
Also, if it creases easily, it will frustrate you. For casual wear, you want to grab and go.
Having said that, I LOVE how it looks on you so much that I want one myself, LOL!