Thank you for your replies so far. Of course I agree that 18 year olds need their parents; at the moment I have three scenarios (one of which involves us staying in Basel and commuting for the foreseeable future).

I so hate the idea of splitting the family; and it's bound to be hard either way. For the first 1-2 years the plan is for me to rent an apartment in Lausanne and stay down there 2-3 days a week. Post COVID is a bit more flexible though I do need to be there quite a bit in person for the first year...

Re permits, yes we have C but submitted application for citizenship. I guess that takes a year++ but hope that will be done or close
to it by end of next year.