well broad scots is a great language, but they are probably not even making that the official language :3 it means a bit of land returning to the EU potentially, I'm not a fan of it splintering, horrible as it may be (and I don't even know why its so horrible compared to the alternative, just people say it)
Biggest gains will be: 1 readmission to EU common market and right of abode in Europe. 2 broadly ability to steer their own future and make their own laws. Scotland is much more liberal than England and would not go the austerity route. Cost? Who knows - imagine Scotland could end up like Ireland with pro-business policies and siphon off international business to some extent.
1. The EU has already basically said they will accept scotland. Spain no longer is threatening a veto for joining. It's a done deal. And just look at Tory vote up north vs down south to answer your liberal question. 2. No it is not a thing. Devolved government can only pass laws that are specifically relegated to them. Look at what that meathead Boris has been up to
1. Not really much to solve financially. They would have to make some cuts but their share of the UK debt is not insurmountable. And yes SNP is not far from labour, but scotland would have a labour government every year for decades. They are constantly having to deal with Tories whom they don't elect.
2. Defense and trade aren't nothing - but the thing they want most is to kick Tory austerity and also to re-join the EU (you will note they can't sign treaties atm)
Their reason for independence is precisely that England and Scotland don't see eye to eye on much - and the fact that Scotland was unilaterally pulled out of the EU. The UK is not federal, it's dictate from England. SNP supporters are sick of being an unequal partner in a union of nations.