I live in mainland Scotland, and personally I am a committed city slicker. I know a few people who live in the western isles, Orkney and Shetland. Some incomers, some locals. They all love it, even though things can be difficult, they feel the benefits outweigh the problems on balance. They are ridiculously beautiful for eg (albeit in quite a different way to say rural England, think cliff and very few trees). Access to healthcare is difficult, but there is lots of health benefits to island and rural life. Healthy life expectancy is higher there than urban areas for eg.
Id agree community is extremely important, volunteering is very normal and necessary, but also rewarding. A great way to integrate and give back to the community. There is a vibrant culture(s) to tap into, for example around trad music and dance, but also art and history. There are some jobs where they struggle to recruit and I expect you’d be very welcome.
I would suggest having DC attend local school if possible would be a great way to integrate, and if considering the WIs look into Gaelic medium education too.
i think the suggestion to go for an extended visit are very good. Personally Scottish winters don’t bother me, but I love long Scottish summer days (always smile when I watch Glastonbury live and it’s pitch black there while the sun is still shining where I live.
Do look at transport connections, especially inter-island, as mainlanders we sometimes assume that if you live on an island in Orkney for eg it’ll be easy to get to Kirkwall, but it hugely varies. Orkney has causeways between some islands, but some where connections are not good at all. Population sustainability is a big issue so while some may not love incomers, I think many know that they are currently necessary to keep island populations sustainable. Inter island transport in the WIs is challenging. My friend finds it easier to fly to Glasgow than get to stornoway.
housing is a massive issue, I’ve heard of people applying for jobs they then couldn’t take as no suitable housing could be found.
it is totally personal, and you might not know until you try, it’s hard to get advice here as everyone is so different. I love the islands, and feel quite passionate about them, but I wouldn’t personally contemplate living on one, I love the city more, but what’s good for me, isn’t necessarily good for you.