Thanks for the post and for bringing this question to the forums, that's the best spot to post it for sure.
So this is always a tricky question and I usually answer it the same way. The hard truth is that if you have heaving in your slab, you'll always have damage to replace no matter the area. Even if it's in the "best" spot in your basement, you'll have drywall breaking plus an uneven floor to repair. No matter where it occurs, you'll have work to do to repair the damage.
The float really isn't meant to stop damage in the basement, but rather to stop damage to the upper levels of your home. I know it's not the answer most people want to hear, but all you're really doing is protecting the upper levels of your home from catastrophic damage. Which would be awful and it makes the float well worth it. But at the same time, you'll always have damage in the basement if heaving occurs and it will probably be expensive to repair. At the end of the day we're really rolling the dice by finishing our basements in these areas and hoping it doesn't happen.
That being said, you can try and protect yourself from small movement by doing the things you're doing. I think you're approach is a great one and if you can find a way to properly "float" that half wall then at least you won't have significant damage. If you've got columns around this area, what stops you from building the half wall an inch or two off the floor and securing it to the floated columns around it? This way if you've got movement it would have to be significant in order to cause any damage.
Does that make sense? Get back to me with more questions or a better clarification of the area and we'll get it figured out!
Thanks Ryan and best of luck!