Gold Coast sent Brodie and pick No.19 to Fremantle at the end of last year in exchange for a 2022 second-round selection and a 2022 fourth-round selection.
The move was essentially a salary cap dump for Gold Coast, with Fremantle emerging as the big winners.
Brodie, who managed just 25 games across five seasons for Gold Coast, is averaging 27.1 disposals and 5.8 clearances in a breakout campaign for the Dockers.
The 23-year-old will come up against Gold Coast for the first time on Sunday when Fremantle travel to Metricon Stadium.
When Brodie arrived at Fremantle there were doubts about whether both he and Fyfe would be able to play in the same team together given their similar roles.
Fyfe has missed the entire season to date with a back injury, but he's on track to return before the mid-season bye.
Longmuir is confident the two can thrive together.
"A lot of teams have two big-bodied mids in their team," Longmuir said.
"There's opportunity for both of them to rotate forward and bring their aerial presence to the game as well.
"There's a bit to work through there before we get Fyfe back, but I think they can play together and complement each other."
Brodie was a highly-rated youngster when he was snared by Gold Coast with pick No.9 in the 2016 national draft.
Suns coach Stuart Dew said Gold Coast's depth of inside midfielders, which includes Touk Miller, Dave Swallow, Matt Rowell and Noah Anderson, meant it was hard to fit Brodie into the mix.
Fremantle are riding high in second spot following their stunning 7-1 start to the season.
Some fans have even got themselves inked with "Flagmantle" tattoos as hopes rise the club can snare its maiden premiership this year.
"I'm happy that our supporters are enjoying our start to the year, but that's all that it is - a start to the year," Longmuir said.
"We've got a lot of work and heavy lifting to do before I'll be getting a tattoo, I know that much."
Rory Lobb, Griffin Logue, Michael Frederick, Travis Colyer, Blake Acres and Lloyd Meek are all available for selection after exiting the AFL's health and safety protocols.
Defender Luke Ryan is in some doubt with an ankle injury while forward Sam Switkowski will miss due to concussion.
