I like the 5th sketch [the center one], i think it can work with some adjustments.
Let me say first that the following are a personal opinion and i hope to not be giving out improper advice. If i do, i apologize.
I think the 5th comp can work with some sizing adjustments, perhaps increase the characters and vehicle slightly while reducing the size of the castle some. Also, you might want to take advantage of the diagonal relation between these 2 elements since they're what primarily builds your composition. I think it can work, the vehicle is closer to the viewer so its contrast will be higher and you'll have a good bottom anchor to the image. I'd also move the castle slightly to the left after resizing it, while trying to keep the overlap between it and the foreground vehicle. However, the comp lacks midground elements so i'm not really sure how to work that out but i'm sure there are solutions. That's just about what i'd have to say on it.