Kirifi was a late withdrawal with a bicep injury from last weekend's 27-26 win over the Crusaders, and Iose took his chance, playing at No8, to score what proved the match-winning try, a solo effort from the back of a Hurricanes scrum.
Holland said the decision was massive, but it was a case of rewarding performance.
"We thought the balance in that loose forward trio [Iose at No8, Ardie Savea on the openside flank and Devan Flanders on the blindside] was good.
"It was a massive call to leave Dupes out, he's been playing well too, and the injury was unfortunate for him. But how those four loosies operate over the 80 minutes will be massive for us to get that result.
"Throughout that bench there's power and explosiveness."
Holland said Savea's shift to the side of the scrum should still allow him to be destructive with the ball in hand. His contribution remained strong when playing that role rather than at No8.
"From [the] set-piece, we have a No8 that comes around the corner, and Brayds does a good job there, but Ards finds ways to get his hands on the ball. There's a good balance between them, and Devan Flanders doing a power of work on both sides of the ball.
In the front row, Xavier Numia has returned at prop to join hooker Dane Coles and tighthead prop Tyrel Lomax, who will play his 50th game for the Hurricanes in the town he grew up in.
The Hurricanes know what to expect in Canberra; they played the Brumbies at the same stage last season, going down 25-35.
The Brumbies have strengthened their side with prop James Slipper back from paternity leave, first five-eighths Noah Lolesio recovered from a concussion and is on the bench, while Pete Samu will start at No8 with Rob Valetini on the blindside flank. Lachlan Lonergan will play at hooker with Allan Alaalatoa still out with a calf injury.
Brumbies coach Stephen Larkham said: "This is the time of year everyone plays for, and we're in a good place heading into a massive challenge against the Hurricanes."
QUARTERFINAL: ACT Brumbies v Hurricanes, Saturday 10 June, 9.35pm NZT, GIO Stadium, Canberra