I must admit I haven't read everything in this thread and I am far from a dog training expert. But I the first thing I taught Capone was his name and sit. When I taught him his name I would say "Capone" and look him in the eye and give him a treat. over and over. I had friends call his name and when he cam he got a treat. Then I started saying "Capone come here" and praise. So know he always comes to me if I say "Capone come here". He might even think thats his full name
Sit is the only other command Capone knows and he does it on command. I think the random reward is the way he learned even though I didn't know thats what I was doing at the time. As we all know it just takes time and patience. You've motivated me to start teaching Capone more tricks again.
I love your Thor's colors, he's a handsome little thing! And he's so smart to know so many commands! Good Luck.