Which is the least likely of the 3 to occur?

[🦀🎂🦀🎂]

from least likely to most likely:

Quebec - ship sailed in the 90's, the youth and minorities don't care about the issue, PQ and BQ both moribund and Clarity Act isn't going away soon. It would have been very interesting if it had happened (how would Canada cope with a massively Ontario dominated federal nation? What would happen to Atlantic Canada? Would people try and partition Quebec? etc.) but it's probably left for the speculative historians to figure out.

Catalonia - it seems like (much like in Scotland) the independence movement just can't pip the majority, and so are left as an angry minority (in that respect, Madrid are foolish in their refusal to respect a referendum, which probably would not pass [the "referendum" organised in 2014  doesn't count] and blunt the movement a bit). The movement has been dampened by the separatist elite, who are basically viewed as self-serving tools; and I imagine a PSOE-Podemos government wouldn't flare up tensions like a PP-C's government would have.

Scotland - Borders on 50-50 at this point. The SNP, despite their success and increasingly fired-up grassroots, has still not raised the YES vote in polls that a referendum can be "safely" called. Various factors will push Scotland away or in - the Euro referendum, the devolution settlement, the realities of EVEL and the oil fields. The increased anti-Scotland feelings amongst certain aspects of the English electorate and the Tory backbenches could be a key push factor.

(in respect to some other perennial proposed map changing: Flanders would be in between Quebec and Catalonia; Unified Ireland between Flanders and Catalonia; Greenland and the Faroes less likely than Quebec - I just don't see them as viable; Kurdistan slightly above Scotland and Puerto Rico extremely unlikely). Perhaps Bougainville is the most likely new country?