Maybe I am too cynical.
* BUT *
Something nags at me about this sort of assumption that the Tories will fall in behind the Lib Dem / SNP plan for a General Election 9 Dec.
Since he has become PM there has always been a trick, a provocation, a challenge to the Commons or the EU.
I can't see it.
Not because it would be a foolish call, but because it would be so out of character.
The Government takes an approach similar to the Lib Dem / SNP proposal - i.e. one requiring only a Simple Majority - but messes with some other aspect of it (i.e. on the election date, or connecting it to the WAB) forcing everyone bar Tories to oppose it?
POSSIBLE
All the election stuff was only a cover for the Extension, and the Government - having given Labour a mighty scare - pulls back from the brink and tries WAB ratification again?
LONG SHOT
It's not the Tories but the Lib Dems and the SNP that are bluffing - once Extension is guaranteed they then aim for a People's Vote again, and a relieved Labour Party now backs this
NO CHANCE - TOO CLASSIC DOM
/ends