The good news is: You can change certain options on more then 1 listing (or all) at once by selecting the checkbox in front of each listing.
The bad news is: the minimum stay period is not one of those options....
If you want to change min. stay for a certain period, you can create a ruleset in the multicalender and apply this ruleset to the listings. It is easier to do, as you don't have to go into each listing to edit it.