There are 24 players with genuine World Cup aspirations across the two sides, including Roosters centre Rob Toia who is in a tug of war between Australia and Tonga.
The Kangaroos will name their squad on Monday, less than 24 hours after fulltime in the grand final.
Among the other potential debutants for Australia are Roosters halfback Sam Walker and Newcastle five-eighth Fletcher Sharpe, who offers versatility throughout the backline.
The Kangaroos open their tournament against New Zealand in Sydney on October 15, where Kalyn Ponga, who previously played for Australia at nines, is expected to make his Kiwis debut.
Newcastle centre Dane Gagai received clearance to play for the Kiwis on Saturday, despite having won seven caps for Australia, the last of which came in 2018.
Both Mark Nawaqanitawase and Angus Crichton, who were both on last year's Kangaroos tour, will be unavailable to Walters as they prepare to switch codes to rugby union.
Kristian Woolf, the Tongan coach, is expecting Toia and his Tongan-eligble teammates Salesi Foketi and Siua Wong to be available for selection in their group stage opener against England in Perth on October 17.
"I'm definitely hopeful of making that Tonga side," said Wong, who played for Fiji at the 2022 World Cup.
The Roosters could provide up to three Australian-born English-qualified players for Brian McDermott's squad, including the uncapped duo of Hugo Savala and Billy Smith.
Newcastle winger Dominic Young and Roosters lock Victor Radley have been mainstays of the English side for the last four years.
"I'm obviously wanting to play and hopefully I get the opportunity to do that," said Young.
"I think we're building a pretty strong team and I think we're excited for what we can do."
After playing England, Tonga face Lebanon before wrapping up their group stage matches with an all-Pacific affair with rivals Samoa at Parramatta's CommBank Stadium on November 1.
Newcastle's emerging backrow duo Jermaine McEwen and Francis Manuleleua have openly declared their intention to suit up for the Toa, where they could be alongside Roosters wrecking ball Spencer Leniu.
A member of the Samoan squad that reached the 2022 World Cup, Leniu said: "If I'm a part of it, I'm going to give my all for Samoa.
"Playing for Samoa, representing our people, is a different level, I don't know what it is, but like there's no amount of money that can pay for the experience that we experienced in 2022."
WORLD CUP HOPEFULS IN GRAND FINAL SQUADS:
Australia: James Tedesco, Robert Toia, Sam Walker, Reece Robson, Lindsay Collins (Roosters), Bradman Best, Fletcher Sharpe, Dylan Lucas (Knights)
New Zealand: Naufahu Whyte (Roosters), Kalyn Ponga, Dane Gagai (Knights)
England: Billy Smith, Victor Radley, Hugo Savala (Roosters), Dominic Young (Knights)
Samoa: Spencer Leniu, Benaiah Ioelu (Roosters), Greg Marzhew, Jermaine McEwen, Francis Manuleleua (Knights)
Tonga: Daniel Tupou, Robert Toia, Salesi Foketi, Siua Wong (Roosters), Tyson Frizell (Knights)
