In terms of what you are asking, my main concern is to make sure that you are really applying to safeties, and that you are taking your budget into account (a school is only a “safety” if you are sure that you can afford to go there).
However, something stood out in your post that I wonder about:
After you graduate from university, do you want to work as a chemist, or as a software engineer? These are quite different.
Why would you want a different major at Stanford? The Stanford web sites states: “When you apply to Stanford, you apply to the university as a whole, not to a particular major, department or school”. I do not think that your chances of admission will be impacted by which major you select (and yes you are competitive at Stanford, and yes it is a high reach).