The NRL's Preliminary Finals will decide which teams reach the Grand Final at Accor Stadium on October 4.
Panthers are heavy $1.28 favourites, despite playmaker Nathan Cleary managing a bone stress injury in his foot.
Boyd and Ropati believe Penrith can expose Newcastle's limited central attacking threat, even with elite fullback Kalyn Ponga available.
Boyd wants the Roosters to progress, potentially allowing veteran halfback Daly Cherry-Evans to complete a remarkable circle.
Cherry-Evans could finish both his rookie and final seasons with premiership success.
Ropati instead supports the Dolphins, whose expansive, risk-taking approach and strong Kiwi contingent could help produce an upset.
The discussion followed the One NZ Warriors' disappointing 2026 campaign and early finals elimination.
The Warriors held a subdued Mad Monday while processing the result, although Boyd and Ropati praised their fans' unwavering support.
They also addressed Adam Pompey's confirmed early release, with the centre reportedly attracting interest from the Storm.