Mr Edwards is a former policeman and fisheries officer who now works as a compliance manager for the Far North District Council.
Mr Rintoul owns a farm at Okaihau and a civil contracting company. He set up his own party, Focus NZ, and ran against Mr Sabin in the 2014 election. He has since made peace with National and now has a role with the party as a rural policy adviser.
Mr Osborne, from Taipa, confirmed he was considering another tilt but had yet to make a final decision. An asset engineer with the Far North District Council, he was "not at all" put off by his bruising encounter last year with Mr Peters.
National's Northland chairwoman, Rose May, said the dates for selecting the 2017 candidate had yet to be decided, but it would be one of the first electorates on National's list.
Unseating Mr Peters would be a challenge and the right candidate would have to be chosen.
"We need to have somebody who is well known in their own right and has that X-factor. If we can find that person, we will have no problem winning the seat back, but if we don't, then it's going to be a struggle."
Ms May said Mr Peters was "the perfect politician".
Grant McCallum, a Maungaturoto farmer who came close to securing the candidacy in 2014, said he was not putting his name forward this time.