I believe that an independent Scotland would seek to establish its own currency ASAP, as most other nations did following their independence:
https://www.believeinscotland.org/how-easily-could-an-independent-scotland-set-up-its-own-currency/
As for being forced to join the Euro, cf with Bulgaria, Croatia, Czech Republic, Denmark, Hungary, Poland, Romania and Sweden.
I would hope that an independent Scotland would be a republic and not part of the Commonwealth, with a democratically elected president. And not Nicola, obviously.