One of the unknowns is what role the Greens will have in Labour's negotiations. Leader James Shaw has talked about making early contact with Peters himself, rather than as a team with Labour leader Jacinda Ardern.
But letting Ardern make the running for the Labour-Greens bloc is the more likely option to find favour.
Shaw in his election-night speech front-footed it by sending a public message to Peters stating some common policy positions such as revitalising rail, a gesture that may have alarmed Labour.
Peters has not yet made it clear whether he wants to repeat of 2005 - when he did a deal with Labour on condition that the Greens were not part of Government.
He and his colleagues are also yet to decide whether to have talks solely with National and turn to the Left block only if a deal could not be struck, or to run a parallel process. The former would be simpler and less taxing on NZ First's limited resources.
Jobs
Joyce's job is off the table. Both National leader Bill English and Ardern have given commitments to voters that the job of Prime Minister and Finance Minister in a National-led or Labour-led Government would remain with the party.
But it's expected both would offer Peters the role of Deputy Prime Minister in a formal coalition.
If the talks in 2017 are like the talks in 1996, discussion of any ministerial posts will come at the end.
Policy
The time-consuming part of the negotiations is all about policy.
It means identifying which policies are completely off the table, which NZ First policies could be adopted, which could be adapted, and which policies of partner parties could be stopped or adapted to better suit NZ First.
But the major parties have to have a mind to their own political priorities, Labour's being health, housing and the environment, and National's being growing the economy.
By now National has identified all the NZ First policies it has in common with the party, those that clash with it, and those on which it's neutral.
Labour is likely to be doing the same. The parties will also have identified policies Peters has called bottom lines -- more ambiguous than a non-negotiable policy.
Ardern yesterday, fresh from Labour taking back all seven Maori seats, declared a referendum on the Maori seats as a "non-negotiable" policy -- that is, she would not agree to have a referendum.
Peters has said a referendum on the seats was a bottom line, but he's had so many that the value of them has dropped. He has also said re-entry to Pike River mine is a bottom line. But National says plans are under way for entry by the end of the year.
The absence of the Maori Party in Parliament may leave some of its achievements vulnerable to change. Whanau ora, a way of delivering social services, is supported by Labour and National but may well be under attack by NZ First. The same goes for the iwi participation provisions written into the Resource Management Act in exchange for reforms of other parts of the act to speed up consenting.
Labour has more policies in common with NZ First but that itself would not be the defining factor in any NZ First decision.
A major factor would be the priority attached to the policy by the party. And sometimes stopping another party's policy is as important as having overlapping policy.
National and NZ First have greater alignment on taxes -- but NZ First might put greater store in stopping a Labour water tax on irrigators or on putting constraints around the tax working group that Labour proposes. Peters opposes a capital gains tax.
But National would be well placed to have meaningful talks with NZ First over some of its infrastructure projects and over regional development.
Labour is more open to Peters' policy to move the Port of Auckland activities to Northport. But English has been careful to rule out virtually nothing from coalition negotiations.
