There’s another factor that just occurred to me: EU nationals living in the UK were not allowed to vote in the EU referendum. They were allowed to vote in the first Scottish independence referendum, so will be in the second.
That’s 150,000 people now very likely to vote Yes.
Additionally, 16-17-year-olds were not able to vote in the first Independence referendum and were not able to vote in the EU referendum, but Scottish voting legislation has changed so they would be able to vote in a second Scottish Independence referendum.
Another very pro-EU group there too, also very likely to vote Yes.