Now, for qualifiers, I live in a full house so things aren't always where I left them (so simply removing searches is useful) and I do cooks both small (just my meal) and large (for the whole group or pre-cooking meals for the work week).
I've always thought of the goal of mise being a sort of process fluidity rather than raw efficiency. Especially with tasks that can't be done simultaneously it's not going to shave much if any time off. But it still leads to less things to keep track of, fewer context switches, smoother transitions, fewer mistakes, more opportunity to notice and account for variations, etc.
You also have to remember that you have the skills and accompany judgement of a once-professional cook. You can cut the celery before the onions burn, but can you cut it before the garlic burns? Could a home cook without a professional background?
It's not that one of those options is "mise en place" and then others aren't. The answers depend on the person doing the cooking, and making that call is part of the mise process for the dish. Having a plan, basically.
It's basically the same thing as 5S methodology in manufacturing. Doesn't make as much sense in a garage workshop, but when what you're doing is the pride of your craft and your day-in-day-out, your setup and tooling should be dialed enough that you almost never have to think about it.