It also would mean you would move the item eagerly, then put it back on error. Or alternatively make it a "ghost" item in the list then remove on success. But overall the eager-move + toast + undo is just a much faster feeling implementation and the overall UX is so much cleaner.
The undo button justifies the toast here IMO. Otherwise I'd prefer ghosting really.
For the checkboxes, I'd say GitHub nailed it: for settings that are applied instantly (e. g. https://github.com/settings/appearance), they show a spinner and then a single checkmark right across the section title. (It used to be next to the input element – both ways are fine, I think)
I agree they do a good job, but I think a toast without undo could also work there. Apply the UI eagerly, toast success or failure. As it is, I assume on failure it becomes an 'X' and shows an error? I just dont generally like very short transitions like the spinner is currently. In general, coming from app land, I prefer a deferred loading spinner that only shows if the action takes X ms. So in the happy path of a fast action the user never sees the loading state.
