The other wing options are Ben Smith and Tamati Ellison - the former a natural centre but selected for his genuine utility value and the latter making his preference clear last week; he'd rather play fullback but is willing to do whatever is required to stay in the 30.
When Kahui and then Jane were ruled out of the June tests, it wasn't immediately obvious who would be called in. Zac Guildford got the nod and Hosea Gear may yet earn a reprieve but, and this is where modern rugby has got to, the fact both are specialist wings may be counting against them.
The All Blacks went off specialist wings in the second half of 2009 when kick and chase exposed the frailties of New Zealand thinking. Back then, the All Blacks held a traditional view that the key skills of their wings should be one-on-one attack, speed, finishing and a bit of X-factor. Joe Rokocoko and Sitiveni Sivivatu were the starting wings until the final Tri Nations game.
A bit late, but by then the selectors had realised that security under the high ball, positional awareness and even a kicking game were more relevant qualities for wings and they have adjusted their selections since by effectively always having two natural fullbacks in the back three.
The evidence is irrefutable. Since 2009, the All Blacks have never had more than one specialist wing in their back three. Jane, who until this year played nearly all his Super Rugby at fullback, has been the most consistent wing selection, partnered by Gear, Kahui, Rokocoko, Sivivatu, Israel Dagg, Smith, Guildford and Isaia Toeava.
The selectors just aren't prepared, having been so damaged by the Boks in 2009 when high balls were spilled and easy points coughed up, to have two 'try-scoring wings' in the back three.
Former All Black wing-fullback and Blues skills coach Jeff Wilson understands why that philosophy stands: "It has gone that way because the role of a fullback has changed so much, you need your wings to be able to fill that spot," he says. "There are a few non-negotiables, as a coach, you look for now.
"The ability to catch the high ball for all back three is crucial. You have to be strong and engage in the tackle; have to have a kicking game to be able to put the ball back up and take territory and you have to be a good communicator.
"Then there is that wonderful thing known as X-factor - the ability to beat people. In the old days, I think X-factor was the priority. But now, teams are so good at analysis and looking at their weaknesses, if you're not strong enough in certain areas, you will be targeted."
There may only be room for one specialist wing in a 30-man squad which means, now that he's committed to New Zealand, Gear, Savea and Guildford are competing for one place. There will only ever be room for one in the starting XV and without utility value, none can command a place on the bench.
The attraction of Gear is his broken field running and ability to stand strong in the tackle when he comes off his wing; he presents a target in midfield that can be exploited by the All Blacks. Savea offers much the same and is in cracking form, his confidence soaring as a result of improving his work under the high ball. He may be the best finisher of the three. Guildford is probably the quickest, the best defensively and hardest working - beating players one-on-one has never been his thing, though.
For Wilson, the key to picking a specialist wing whose main offering is X-factor is to minimise the risk.
"When you are looking at players, you have to make sure the positives outweigh the negatives," he says. "[The key] ... lies on the scoreboard - if he's getting you 14 and only costing you seven ... no problem. But if the ledger is not balanced and he's not quite creating for you, then you have to take a conservative approach."
For the romantics, there is something not quite right about the current state of affairs. Rokocoko in full flight in Cardiff eight years ago remains one of the enduring memories of the Graham Henry era. Sivivatu ambling then splitting defences was magical. Rico Gear's hat-trick in Cardiff 2005, where he twice pulled off outrageous in-and-out moves, was attacking play at its finest. Yet the All Blacks wouldn't have won the World Cup had it not been for the security and aerial brilliance of Jane and Kahui.