You would most likely miss Kindergarten Graduation and possibly an Award Ceremony, Transition to 1st activities, report cards, year end project presentations, Field Day, and any other year end activity (picnics). They may also be doing year end assessments/testing and reviews for placement next year and report cards.
I would not miss the last week personally unless it was very important (which depending on how often you have reunions could rate the reunion as very important). It provides a needed transition for the next year---I would miss the second the last week if given a choice-- -not many academics may get done, but a lot of 'closure' activities take place as well as an opportunity to get ready for the next grade and participate in activities to say goodbye (for the summer) to friends.
Given that you have a family event- it is a toss up and a hard choice- your DD may feel very sad missing out on either school activities and/or the family event.
I dont think that it is just kindergarten has any relevance- the last week of any year K-12 would have them missing transitional activities and provide closure for that year.
Talk to your DDs teachers and see what is going on those weeks. It may not be a big deal if they planned on wrapping it all up on the 'old' final day of school anyway and the last few days will be filled with more relaxed activities.
You will likely get varying opinions since there really is not right/wrong answer. Some people regularly take kids out for family functions, others rarely take kids out of school unless they are ill. Depends on your family philosophy and the schools policy (they may frown and/or have disciplinary plans for kids that miss too many days in a year for non-illnesses).
Make sure your school does not have a set number of 'unexcused absences' (vacations) that if you go over that number you can be called to truancy court/fined/file in students cumulative records. Our area is more than 5 unexcused absences and 10 excused (sick) absences total- exceptions made for hospitalizations and/or Dr notices of lengthy illness. And yes, here they report parents to a truancy officer and too many unexcused can cause a student to repeat a grade regardless of academic standing. Some areas have no policy- find out yours.