Concluding this, the theory states that both the counterfactual statements ``If A had not been open, we would not have seen the man with the hamburger'' and ``If A had not been open, B would have been open'' should not be accepted.
If after working this out I still have any such thing as intuitions or opinions about these counterfactuals, then I very much agree with this result: When constructing a possible world in which A had not been open, to keep our thoughts consistent, we do not necessarily need to remove the hamburger-man and we do not necessarily need to open the other snackbar.
All we need to do, is do at least one of these things.