To be fair there's a not insignificant chance of pro-independence parties falling short of a majority. Polls currently put them right at the edge of one. If they lost their majority you'd see them need to get an agreement with CQSP/CeC (basically Podemos's brand there), which while firmly in favour of a referendum, reject unilateral moves.
So depending on how much both sides want to compromise and what the Catalan government wants, that opens many possibilities, like ERC-CQSP-PSC, ERC-CQSP-CUP or ERC-CQSP-PDECat. Maybe even a minority ERC-CQSP government with PDECat and CUP abstaining.
But yeah, if pro-independence parties get a majority things will repeat themselves.
Also, funny how you mention banning secessionist parties, as the Catalan PP leader Xavier Garcia Albiol and other PP hardliners mentioned that possibility reciently:
http://www.lavanguardia.com/politica/20171016/432123007829/xavier-garcia-albiol-prohibir-programas-electorales-independentistas-elecciones.html?utm_source=Twitter&utm_medium=Social
I don't think that happened though. Even banning Batasuna (which had ties to ETA) was already quite a stretch on the limits of what was constitutional apparently.
Wouldn't joining a coalition with independentist parties be a suicide for CQSP-Podemos?
