The Australian won last year's A-League title under Montgomery at Central Coast Mariners.

Late on deadline day, a deal for Sunderland forward Eliezer Mayenda, 18, was also announced.

The Spanish teenager has featured eight times for the English Championship side since moving from French Ligue 2 Sochaux.

Triantis, who has made just two starts for Sunderland since signing a four-year deal in June, has been capped at Under-20 and Under-23 level and was named in the PFA A-League team of the season last year.

"I signed him for the Mariners and gave him his A-League debut as I saw huge potential in him," said Montgomery.

"He was a mainstay in our Championship winning team before joining Sunderland in the summer. Although he might not have played much, when he has featured, he's performed well.

"We have been chasing Nectar for some time, and although we thought he'd remain at Sunderland, circumstances changed last night, and we made a move to bring him to Hibs."

Bevan is a Wales U-21 international and spent the first half of this term at Cheltenham Town in League One.

He is third player to make the switch to Easter Road from the Cherries this month - after Emiliano Marcondes and Nathan Moriah-Welsh - with Bournemouth owner Bill Foley due to take a stake in the Edinburgh club.

"Our relationship with Bournemouth allowed us to look closely at their young players and Owen was one that stood out instantly," explained Montgomery.

"He is a young centre-back with great attributes and a fantastic attitude. He can play either side as a centre-back and at right-back, which provides us with great depth and competition for places."

The opportunity to sign Mayenda came after Harry McKirdy was loaned back to former club Swindon Town. Fellow forward Christian Doidge left Easter Road for Forest Green Rovers on Wednesday.

McKirdy, 26, has been working his way back to fitness since undergoing heart surgery in the summer.

"When the interest came for Harry we had a good conversation and we felt that it would be a good opportunity for him to get more game-time than what was potentially on offer here," said Montgomery.

On Mayenda, the head coach added: "He's a powerful, attacking player with lots of energy who can play both central and wide.

"At 18, he's already played Championship football and is highly regarded at Sunderland with a big future ahead of him."