I may be wrong but I thought that if a new country now applies to join the EU they are obliged to adopt the Euro currency, therefore no more pound.
You're absolutely right - I believe it was actually part of the Maastrict treaty, we just got an opt out.
If you join the EU now, you're legally obliged to join the Euro. Although first your economy does have to be in regulatory alignment with the EU's, and I suspect Scotland's is way off. So they'll first be obliged to substantially reduce their deficit-to-GDP ratio. Meaning hello to more austerity.
They'll also be legally obliged to join Schengen, unless the EU gives them a special opt out.
Of course, this is assuming that the EU agrees to let them in in the first place. Spain may have something to say about that, if it wants to send a message to the Catalans and Basques.
That all being said - I lived in Scotland for several years, and have many Scottish friends. Almost across the board, they voted to stay in the Union, but most did so slightly grudgingly.....wanting Scotland to be an independent country, but realizing that it was probably economic suicide to do so.
If the UK does finally leave the EU, and
if that does have some negative economic impact north of the border, then I suspect they would all be switching and Scottish independence would win in a landslide. Especially if the EU made positive noises about letting them in......