Hey Michael,
I like the original as well, though I can definitely understand wanting clouds.
I am not sure I like and of the 3 samples. Thinking about it, this image doesn't have much sky, so it would be hard to get the nice large puffy clouds I was imagining would be nice.
I think #3 has the right idea, though it doesn't quite work. With Alan's choice of #1, maybe if the clouds were less magenta looking it would fit better.
I just thought of this.... in the Milky Way circles I am sure you have seen where it's very popular for people to capture their ground layer at twilight, and then later that night go to an area where the land is often flatter to use a star tracker and capture a dozen images of the Milky Way to stack with the original ground layer taken at twilight.
I personally am not a fan of this, I don't mind blending images at night from different times, but I do believe that it's wrong to move the tripod to a new spot, which is sometimes miles away from the ground layer location to then use. Most of the people are upfront about it, which is good, but that doesn't mean I like that idea any better...
So.... all of that said to where maybe you should just take some of your clouds from previously in the day and then blend them in this image? If it's okay to do it with Milky Way images, maybe it should be okay with regular landscape as well? I am not saying it is, or should be, but I think it's something to consider these days as we blur the lines between reality and acceptable composites.