Indeed, i suspect the DUP will see this as a way of getting further concessions in return for their support as it may imply a very different change in circumstances.
Another interesting point is that i doubt this leadership battle will actually increase Conservative unity, i suspect it might actually make the factions more hostile to one another than they were under May. We already have Conservative 'moderates' launching a 'Stop Boris' campaign:
https://www.theguardian.com/politics...hnson-campaign
Both in terms of him getting to the leadership, but also its been stated here and previously that significant numbers of Conservative MP's would be willing to vote down a Boris government if he pursued a 'hard brexit'.
They are helped in this by Labour, who are considering the idea that any new Conservative leader who does not immediately call a GE to gain a mandate, will be face a vote of no confidence initiated by Labour.
https://www.theguardian.com/politics...john-mcdonnell
This presents a major issue for any Conservative candidate who does not unify all parts of their party (Which Boris does not), as it would plunge them into a new GE, which most opinion polls currently have Labour on a clear lead.
It's also why in terms of leadership prospects, while Boris is the favourite, i don't think he will be allowed to get to the membership vote. He'll split the party too much (And indeed see open revolt potentially it seems). The same though goes for any other Brexiteer or remainer/Soft brexiteer who is taking a hardline approach. This isn't going to be pretty for the Conservatives, and will definitely cause more problems both for their political position, and their party unity than it resolves, it certainly will put internal pressure on any new leader to try and gain a real majority as its not clear they'll have the entire support of the party behind them, they may even be worse-off than May was in this regard. (This all pending some new unifying candidate, who i can't actually see at the moment).