Good for you for volunteering to teach those kids. Building any skill like sewing can make a huge difference in terms of confidence and self-worth.
You have an advantage because the kids you're teaching are high school level and want to be there. That makes a huge difference. They will all at least be trying. Maybe after going over the basics have them make a few test seams to see what their skill levels really are. That can help you determine which patterns to let them choose from. I think it's important that they're challenged at least a little bit so they won't get bored.
DP4 might be a good pattern too. Still pretty easy but looks tough to do when it's done.
Rodney