Which island should we go in Hawaii as a family?

We are planning a trip to Hawaii in two years. It is for two weeks (if we bring the kids) or one week if we decide without the kids.

We are thinking either…

Big Island, we haven’t been on this island before (thinking west side..snorkeling turtles..dad and son helicopter tour to the volcano, seahorse farm)

or Maui / Lanai (we loved it when we were there before) the towns of Wailea, Makena, the mountain at sunrise.

or Kauai where we have not been before.

We would love advice. Thanks in advance. Our kids will be 8 and 4 in two years.