I tried your suggestions with varying results that I didn't understand.
1. I took the focus group I had started with the ancestors of my gr-gr-grandfather and using your suggestions I added the spouses of the ancestors and then in the next step I added the children of the ancestors. When I looked at the focus group list it appeared that I had what I wanted. However, when I ran the list of the people in the focus group and created the new project and dataset, I only got the original 102 ancestors in the new project and not the 250+ that I added with the last two steps.
2. I then deleted the people in the focus group along with the new project and dataset and started over. Creating a new focus group and doing all three steps before I saved the focus group. This time when I ran the list report and created the new dataset and project I got most of the focus group but still not all, missing less than 20 this time.
3. Starting with a new focus group again and following your steps, this time I tried to copy the people from the focus group to a new dataset in the same project using the "copy persons" command. I got better results but was still miising a few people from the focus group.
I also realized I was missing the some ancestors from wives of the children that I wanted. I think that is my fault in not trying to pull ancestors again after I selected pulled Spouses. I will be experimenting more over the next few dys until I get a better move to a new dataset so I can merge it with an existing project.