The following question is important to me: I set 5 days as a minimum stay for the summer season. But the guests book the accommodation in a way that there are 3 days (vacancy) between the two booked periods. Can I only set it manually that the remaining 3 days also can be booked?
Yes, you may allow staying for this short period by creating a new special season for those 3 days only. Then you will need to add this season to the rate above other season prices.