From that description, I would not even try a halti, she would freak out with it.

What you have is the easy walker harness, also made by the same company as a halti. As long as you are satisfied she can't get out of it and dash off, that is fine. She isn't really "choking" with that, as it isn't around her throat.

If you think she "could' get out of that too, you may want to try a rope n go harness. I have one for Tasha, my mill rescue, only thing I found which she could not escape out of. See, the first thing is safety of the dog, so you don't want her to get out of whatever.

For the walking issue, you can take treats and a toy with you. Soon as YOU spot a distraction, (which may be before she does), you get these out and get her focused on you. Keep her attention until the squirrel is up a tree, the cat is under a car, the other dog has passed.