EU referendum, brexit and the aftermath

If this looks like to happen will it be enough to get the 21 tory rebels to get behind a vote of no confidence and put together a government of national unity.

I don't think a VONC can help. If you lose a proper[1] VONC then you have 14 days to win a VOC otherwise the General Election is triggered. If all of the above starts to kick off on October 19th/20th (after the EU summit) then 14 days takes it past Oct 31st.

1. As in a VONC in HM's Government. A VONC in an individual (i.e. the PM) has no binding action.