I suspect that those who want to separate Catalonia from the rest of the country wouldn’t agree with the human right of the people in the Barcelona metropolitan are to choose by themselves their own future...
Just start the political movement and it'll be respected. I think it's a fair ask.
By the way, can I get your crystal ball? There's this lottery thing...
Aran has its rights explicitly recognised by Catalan Parliament, including their self determination rights, right now: https://cat.elpais.com/cat/2015/01/23/catalunya/1422013790_5...
Rahola hasn't been a politician for decades. ERC is much better than it was with her and Angel Colom.