The best way to figure out your family relationships here on WikiTree is to upgrade to the Family Member level (completely free) and begin adding what you know to your branch of our tree. As you add each generation that you know in your family, you might find that someone else has added one or more of your ancestors. That will be an opportunity to collaborate and maybe find more information until you either link into the descendants of Robert E. Lee - or find out that your family does not link to his. Either way, you will find out a lot about your family and maybe extend them upward and outward.
Good luck with your research and we look forward to your contributions!