The way I read it Labour will regain the Red Wall, many metropolitan seats and already have enough for a small majority but the SNP implosion could give them a further cushion of 15 more seats. If Lib Dems pick up seats that could store up problems further down the line.
Except that the geographical area of Scotland has been part of the EU for almost 50 years, voted overwhelmingly to remain and is used to adhering to EU rules, so a totally different and unique case to other candidate countries. They won't need favours to be able to pass compliance rules.
I don't see this as anything other than short-term logistical issues. If the EU will entertain admitting Moldova, Ukraine they'll fast track Scotland back in no time. Scotland is as much of a historic country as Croatia who also had no government or currency as they were governed from...