Another one here who is struggling to understand the decision you are making here OP.
I moved up with family 15 years ago, my second stint living in Scotland, and moved up very much 'eyes open' to the challenges of rural Scottish life. Since then (and a divorce) I have now moved somewhere with more facilities, on the railway and main road network, with a doctors in the village and a hospital within an hour. I am much happier.
Island life is something else again - and if you have never come and spent a couple of weeks in January on the island or remote coast you are considering, then you really, really need to.
Rural in Scotland is also of a different scale to rural in England. I used to drive an hour after school so my kids could learn to swim. Each way. Getting to secondary school for some local kids was a 1mile walk down a driveway (pitch black in winter), 8 miles on a landrover, then 27 miles on a bus. The kids left home at 7am to get to school on time, and got home at 5:30 or so....Every food shop was a 16 mile round trip to a tiny CoOp - a proper supermarket once a month was a 70 mile round trip.
Remember that school is different up here - a different curriculum and education system. As a teenager your son is right at the difficult point of the education systems being different - you need to do research. If you are very rural and remote, the school may well be boarding as well (paid for by LA). Do you want to be split up each week?
Jobs are also tough rurally - unless you want to drive to a town or similar, which could be an hour or more away. Past that, you are looking at lots of low paid, seasonal jobs for many.
As an ex-landlord, I would never rent a property to someone I did not know. And frankly at the moment the holiday let market has devastated rural long term rentals. You will be in a queue of 17 other people - and if you are not prepared to be here to view, you will not get a house.
Remember as well how crap the weather can be, particularly at the shoulders of the year when the weather can be something else compared to where you have been living. Add in dark winters, higher costs of heating homes etc, and winters can be tough.
All that said, I love loving here and would not move south of the border again. My view is the education system is better, quality of life higher, houses cheaper (but you spend more on heating and travel for the most basic of supplies). The community feel is totally different up here, and I love it.