Willrob, I think you are making the classic mistake of doing your family research by copying other people's family trees. You say you are confused because some names in other people's trees match your tree while others do not. Obviously some of the trees are in error and the only way you can be sure is to go to the original reference, i.e. birth certificate, parish register etc. Other peoples family trees are invaluable as find aids but always treat them with suspicion and recheck the information they provide.
So many people, in their haste to get further back into their family history, make assumptions and assumptions are not facts. However they present these assumptions as fact and that is where the danger lies.