The extension of Article 50 until October 31st does nothing to help Theresa May get a deal through the House of Commons. It's looking increasingly likely that it will instead be used for a Tory leadership challenge.
There's simply not enough time for anything meaningful to happen between now and October 31st. Even if the negotiations between Labour and the government bear fruit in the form of a customs union, Labour may still be split if the idea of a confirmatory public vote is not in the compromise deal. As well as this, in the unlikely event that the government agree to a customs union in the negotiations, they would be facing mass ministerial resignations leading to a change in leadership or a number of Conservative backbenchers leaving the party.
As much as I'd like a second referendum, it also looks unlikely to happen in this extension. Whilst six months may be just enough time to hold one, there is a huge task for MPs campaigning for another public vote - they have to convince a majority of MPs in the House of Commons to vote for a referendum. Moreover, this has to be achieved in a number of weeks, not months. In the short term, this looks incredibly unlikely because until all the other options have been exhausted, moderate Conservatives will not have a motive to vote to take the Brexit process out of their hands.
Even if the government's hand was forced by parliament to hold another referendum, they could be out of power within days, given the huge opposition to another referendum in the Conservative party. A general election also seems unlikely, given that a no confidence motion still isn't winnable without the support of some grouping of the DUP, the Independent Group and a dozen or so Conservative backbenchers. The government are also absolutely terrified of a general election, especially with May at the helm and with the recent polls predicting a Labour victory.
All of this means that we will probably end up in the same place this October, with no deal ratified and maybe an even more Eurosceptic Prime Minister.