You need to present your log books, licences etc to the authority and they will tell you what you have to do. This will almost certainly involve doing the JAA written exams and probably doing a flight test/instrument rating as well.
The wannabe forum will have people more up to date with the current requirements.
Yes, if you have a EU nation passport you can live and work anywhere in EU. If tou have a JAA licence you can fly anywhere too, though some countries may still require local validations. So, if English is your native language you might be better doing a UK JAA ATPL.
As to residency, it depends on just how close your Scottish relatives are.
hope this helps