North coach Brad Scott confirmed on Wednesday that Wells would return from a one-week suspension and Hansen from three weeks on the sidelines with a hip injury.
Macmillan will play his first senior game after fracturing his fibula in round three - two solid games with Werribee in the VFL enough to earn him a recall against the Demons.
Preview: Kangaroos v Demons
Scott said North would consider resting first-year utility Luke McDonald and veteran defender Michael Firrito against Melbourne.
But the Roos coach said his team was not about to take the struggling Demons lightly given a number of North players would be playing for finals spots.
"I don't look at it as resting - the way we look at it is we've got some good ins: Wells, Macmillan and Hansen will come into the senior side, (Robbie) Nahas (shoulder) will play in the VFL, (Joel) Tippett (calf) we hope will play in the VFL," Scott said.
"But with that we've got to be smart. I think that Luke McDonald has had an exceptional year … he's easily in our best side, but he's played every game this year bar one that he missed with illness.
"So he's one we'll look at maybe whether he needs a spell or not just to get him cherry ripe for the week after.
"Probably Michael Firrito is the other one, who has been exceptional for us this year, but he's carried a really heavy workload."
Scott said North's list was in the best health it had been all year, and expected competition for spots in the Roos' elimination final team to be fierce.
The Roos coach said Wells had completed a match-simulation session during his one-match suspension last weekend.
Wells has played just one senior game since round five, in round 21 against the Western Bulldogs, but Scott is confident his star midfielder will enter September in good shape.
"He's in really good condition. It's been a long steady build for him," Scott said.
"We saw him play pretty well against the Bulldogs and we think he'll build on that performance."
Scott said Macmillan's recall after just two VFL games reflected the standing he was held in at Arden Street.
"(He's) an important player for us, a really smart player, a good emerging young leader," Scott said.
"He has had a good steady build-up, played reasonably well last week, but his last start in Frankston against Frankston was really good.
"We think he'll come in and have an impact, but he's going to have to fight for his spot like a lot of others."
Nahas has not played since injuring a shoulder against Melbourne in round 14.
Scott said the former Tiger's ability to complete a lot of conditioning work during his time on the sidelines meant he could earn a quick senior call-up if his VFL form warranted it.
The Roos coach also welcomed this week's news that North had reached an agreement to play three home games a season in Hobart for the next two years.
"It's terrific and it's great that the people of Hobart have embraced the footy club because we have certainly embraced Hobart and we need to build new markets and we want to build our supporter base," he said.
