The main characters would most probably be the McKinney brothers. Depending on the plot, there could be other important characters like their parents who might play a role in influencing their romances. And of course, the love interests of the McKinney brothers would be key characters too. They could be from different backgrounds, which would add to the complexity of the relationships in the novel.
Since I don't know the specific McKinney Brothers Romance Novel, I can't say for sure who the main characters are. But it's likely the McKinney brothers themselves would be main characters, and perhaps the women they are romantically involved with.
In a typical McKinney Brothers Romance Novel, the McKinney brothers are bound to be the central characters. Let's say there are two McKinney brothers, John and Mark. John might be the more serious one, while Mark is the carefree type. Their love interests could be named Sarah and Emily respectively. Sarah could be a strong - willed journalist and Emily a kind - hearted teacher. These characters would interact, fall in love, face challenges together, and their relationships would form the core of the story.