Minimum paid tenure could be negotiated and put into the Termination part of the contract. Think about how you would feel if it ended in a year or 18 months, or whatever. For example, you could ask for 1 year at full rate and remainder of second year at 3/4 rate for any early termination to compensate you for the major non-financial aggravations of moving. It would cost them nothing extra if they are truthful about the job.

Kids flexibility to change depends on their personality and a lot on their age. Pre-teen adapt quickly to change, make new friends, etc. Expect no more than a month of moaning and groaning. Teens are bad news by comparison. Breaking into established cliques in school and in the neighborhood is more difficult. They have to reestablish who they are in the scheme of things. Initially, they link with other kids who are also "new". It helps to be in a place that has "new" kids. Teenagers will bitch and moan for up to two years. Then they are glad you moved. That's been my experience moving from Upstate NY to Charlotte. And, sorry, kids do no decide whether or not you move unless they are contributing to family income.

Climate is not a major factor unless it affects you mentally. If you can have fun in it year-round, life is good. I would not worry about "thin" blood.

This is real life and not, as they say, a dress rehearsal. If your dream is to be AK, go for it.