1) Polls continue to point to a significant “yes” victory in a future referendum on independence in Catalonia.
2) If the Catalan government backs down from a referendum, even if the Constitutional Court declares it illegal, as it certainly will, it will pay a heavy price at the polls. Therefore, it is locked into holding a referendum, unless it can negotiate a sufficiently advantageous fiscal settlement with the Spanish state. A negotiated settlement averting a referendum remains the most likely outcome, although p<0.5.
3) Some Catalans think the Socialist Party of Catalonia, which is linked with the main Spanish opposition party (PSOE) and has been trying to straddle the self-determination issue, will implode soon over the issue.
4) Catalonia and Spain may both be more viable as separate states than together. Spain's political economy is dysfunctional. Catalonia’s would not be (the largest Catalan party is centrist with some classical liberal elements). A functional state can carry a larger debt burden than a dysfunctional one. Therefore, the European Union might pressure Spain to accept a post-referendum settlement by which Catalonia is allowed to go free while taking on a disproportionate share of Spain’s debt. (On this point I am indebted to Jaume Lopez Hernandez of the Universitat Pompeu Fabra.) This is the second most likely outcome.
5) Spain’s threat to arrest Catalan leaders and prevent secession by force is not credible. (Although some autonomists and secessionists in Spain insist that the central government would indeed send in the tanks.) Therefore, it is unlikely that the Catalan government will be deterred. A “yes” vote followed by suppression is the least likely outcome, even less likely than a “no” vote.
6) If the Catalan referendum is held, regardless of the result, it would set a powerful precedent for Basque nationalists. The precedent is not that secession is easy or desirable, but that the possible legal framework will be recognized. The Basque Premier backed down from holding a referendum on his “Ibarretxe Plan” for free association after threats of arrest and a negative vote in the Spanish Cortes. The reason why I argued, in this interview, that Ibarretxe should have gone ahead with the referendum is not so much that I endorsed the Plan itself (on which I am agnostic), but that I fear his backing down set an unfavorable precedent for the “right to decide,” which I do favor.
7) Nevertheless, even if Catalonia secedes, the Basque Country Autonomous Community is unlikely to follow, at least right away. Pan-Basque independentists are a powerful force and would insist on bringing along Navarre (and later the French Basque provinces). But Navarre would vote “no” in a referendum held today or at any time in the near future. No other region of Spain is likely to hold a referendum either, and thus there is likely to be no “harmful precedent” for secession or “contagion” from Catalan secession.
PILEUS 
You speak of a “sufficiently advantageous fiscal settlement with the Spanish state” though the “right to decide” goes far, far beyond that! I fear that too many Catalans have simply lost any faith in Spain’s ability to meet its commitments. Moreover, Spain’s almost instinctive centralism will threaten the Catalan people as long as it gas the last word. The largest demonstration in Catalonia’s history, last 11th September, plus the rapid growth of the “Catalan National Assembly” ( http://www.assemblea.cat ) and the declining support for federal solutions, are clear signs that Catalonia has had enough.
Mention might be made of growing calls, if te referendum is blocked, for a plebiscitary election or (if even that is deemed impossible as claim some Spanish sources) a unilateral declaration of independence.
Right. I still think it’s possible that when the Spanish government reviews its options, it will look at a fiscal settlement as the least bad option from their perspective. Similarly, the CiU would only be willing to pursue a UDI as a very last resort, and have left a window open to not holding a “plebiscitary referendum” on independence if a very generous fiscal offer were on the table. There could instead be some form of referendum, perhaps legally authorized by the Spanish state, on accepting the fiscal settlement. Again, I’m not saying that this is likely, only that something like this is the most likely of a number of possible outcomes.