Does She have any off-leash time? Other than in the house, do You have a yard that She can run in?
At Her age my dog got the zoomies, ran the length of the yard, turned circles on bushes, ran the other way and jumped up at me as she went by, just kind of went batsh*t crazy (in a happy way). I walked my dog A LOT (not as much as You, but A LOT), walks are very controlled exercise (about 2/3 slower than they want to go and no detours for squirrels, kids and poodles)and she seemed to need that little 'umph' to burn off some of that teen angst.
If everything in Yume's life is controlled then She doesn't really have a good outlet to express her dogness.
Walks and treadmills are a good workout for the times that they need to use their energy (like chasing a bear) but they don't get that endorphine release until they really cut loose. That's like an athlete training for race day but race day never comes.
Akitas are really hard to burn down because they won't fetch or play like some dogs and they hold too much energy in reserve, especially at Yume's age. Free play, like wrestling with another dog or chasing water from the hose or a sprinkler in the back yard, if You can figure out a way to run her down you'll both be happier. I think it's true, a tired dog is a good dog.
Like I posted before, if this dog was out to get you then you'd be hurt and she'd be gone.
The "ha ha ha" sounds are kind of like laughter, when She's in a cuddly mood try lightly nibbling her cheeks and under her chin with your finger tips and eventually she'll make some "ho ho ho" noises.
Blah, blah blah, sorry.
Best wishes and good for You going the extra mile for Her.