It also emerged yesterday Brad Thorn will be making a decision on whether he joins the Highlanders within the next 10 days.
The Highlanders announced yesterday Emery and Coltman had both signed three-year deals with the franchise.
Emery has only just turned 19 but is a classy, skilful centre, who has plenty of potential, and has played well in his first year of first class rugby.
He attended Palmerston North Boys' High School and was in the New Zealand Schools side in 2010 and 2011.
He was also a member of the New Zealand under-20 side which lost in the final against South Africa at the World Junior Championships in South Africa.
Coltman, who turns 23 in January, first played for Otago in 2010, and was in the Highlanders wider training squad this season before being laid low by a neck injury, which at one stage threatened his season.
But he has bounced back with an outstanding effort for Otago in the ITM Cup, which has seen him rewarded with the Highlanders contract.
He has been picked as a hooker for the Highlanders.
It is highly likely Coltman will have some provincial company with Otago first five-eighth Hayden Parker and halfback Fumiaki Tanaka likely to make the Highlanders squad.
Parker said at the weekend he had not heard anything from the franchise but with the Highlanders squad going to 35 next season he is highly likely to win a place.
Tanaka is in the same boat and he has impressed for Otago this season.
Foreign players are allowed in Super 15 teams - one per team in New Zealand - with English international James Haskell playing for the Highlanders last season.
Tanaka, who plays for the Panasonic Wild Knights in Japan, could argue to qualify as a local player as he played club rugby for Zingari-Richmond this year.
Meanwhile, Thorn's manager Brett Gamble said Thorn had not signed any contract for next season but a Highlanders contract was one option on the table.
Thorn's options after the Japanese club season finishes included having a rest, going to Europe or playing for a New Zealand Super 15 team.
When asked if Thorn, who turns 38 next February, wanted to come back and play for the Highlanders for one last season, as he was born in Mosgiel and started playing rugby as a youngster in the province, Gamble said there was some "symmetry" in that.
"It is his home town where his dad played some rugby. But whether he is ready to finish is another question. He is still a fairly resilient guy, still pretty competitive.
"I wouldn't be saying this would be his final fling with rugby ... he is still very fit and still very motivated."
The first 28 players of Super 15 squads have to be named by franchises by October 23 and Gamble said any decision by Thorn would have to be made before that date.