I can't imagine May running a separate NI ref when she's relying on the DUP to prop up her non-majority.

I think the plan is to stall for time and crash out.

Psychologically, May is an extremely dangerous person. Every single thing her government has done has been violently angry, destructive, dishonest, and abusive - as the NHS, the police, the EU, and the various victims of institutional xenophobia and racism will confirm. (Among many others.)

So i think it's realistic to expect her to pick the option that will do the most damage to everything around her - which of course is a no-deal car crash.

When you consider that rich Tories will be able to move their money out of the UK, wait until the pound crashes, then buy up the smoking rubble on the cheap, there's no particular reason for them to want a deal.