I LOVE the first image. There is lots of contrast, it is well centred and I just love the overall mood. I did not notice any focus issues.
2nd image- I agree with the rim of light around the couple. It makes it look like they we cropped form another photo and pasted in. It would be nice if the moon were a little brighter. I do love the composition though.
3rd image is a little too dark to my liking. And he should have worn a different coloured shirt because his right arm is missing. Unless she really is supporting herself like that. Good strong back muscles! I like the pose.
4th image My first feeling is centre it more. My second feeling is back up and un-center it more. Put the couple to the left of the image with stairs leading up to them and maybe just a hint more light on the stairs behind them, just to give it more depth.
Just my 2 cents worth (in Canadian dollars)