Like I said on Linkedin, great article! A few thoughts:
It seems to me that the examples you list as "dark patterns for good" aren't really dark patterns at all. They are simply psychological tricks that get users to do what they already wanted to do. I would define dark patterns as using psychological tricks to get users to do what they DON'T want to do, or something that would benefit the company, but not the user in any way. That's what makes them "dark". Otherwise, they are simply "patterns".
The experiment with your kids is a little different. You have goals that are different from their goals, initially. The cool thing is that their goals actually change as a result of the experiment. They become more conscientious of the environment. They start to align their goals with yours.
I have yet to see a product or business that does that... has separate goals from their users to start, but actually changes those goals to align more with theirs over time. Maybe it's only possible to do that in a forced relationship (such as between parent and child)?