As for me, the fact that you are planning a tour with your family for a year is very cool, it is better to be prepared for everything (especially since you are 16 people lol). True, I can say that the trip will cost you a considerable amount of money. When I went to Switzerland for a vacation, I found one site
this page to save a little, where you can learn how to save a lot. It will be helpful to you. As for renting a house, I recommend that you pay attention to a chalet somewhere in the mountains (for example, in the Engadine valley), but I recommend booking in advance. In winter, especially on Christmas Eve, it will be very magical. I hope your trip goes well