From a practical point of view, you will all need to drive. You will need a non complicated car that the local mechanic can handle, nothing requiring specialist main dealership attention.
You child will be OK when a child, but teenage years are hard on the islands. There's no work unless you know people who will take your teenager on in the local cafes in the summer.. "knowing people" is crucial for employment really.
Everything costs more as it's got to be imported... Counter that with minimum wages and you often have 'London prices' on minimum wages. You will need savings. Yes, work from home online can bring in better money, but Internet connections are very, very unreliable.
In winter, you'll need outdoor storage for wood, cars, anything not tied down that can be ripped from the ground in 100mph winds. You will need patience. It's very annoying constantly replacing guttering, roof tiles, window panes,... Did I mention costly???
The key to everything is people, getting involved with the community, helping out. When times are tough, you'll need others...
It won't work if you keep yourself to yourself and don't have mega money in the bank to give you child opportunities to leave, work, study later... :(