The answer to all of the above would to become a wholly integrated EU state with a hard border at Gretna. I'm not sure of the exact figures, but I think the Scottish economy would currently be running to high a deficit and missing other criteria for EU/euro entry? The SNP need to maintain support, have another referendum and do both at the same time as oil prices recover to make a go of it.
They’ll likely spend several years outside of the UK and EU, this will absolutely fuck them.
Trainspotting will look like utopia at the end of that period and the EU wouldn’t want them.
It’s the epitome of political delusion.