What commands do you consider essential?

That seems like you have most of them covered. The real test will be getting those commands to work through distraction. Obedience doesn't really help if it only works at home with no distraction and you can't take your dog for a walk around your neighborhood, around town to show him off, or if you ever have to travel with him. Check out the videos at www.sitmeanssit.com They are a great group of trainer that pride themselves on being able to work their dogs anywhere anytime. Hope this helps.