Brennan is yet to coach at first grade level but is thought to be a promising coach that will have a successful career in the NRL. He has been linked to the Gold Coast Titans, who are likely to sack current coach Neil Henry this week. Brennan has coached lower grades at Penrith and knows a number of the young Kiwi players.
Former NRL star-turned commentator Matthew Johns nominated Brennan as the game's next great coach.
"I've had a rap on fellow named Garth Brennan for a long time," Johns said on his Triple M radio show.
"Brennan has been coaching lower grades at Penrith for a number of years now and he's won competition after competition.
"He's a young coach, he is very much in that Trent Robinson, Michael Maguire mold in the fact people don't know who he is.
"He's not a household name in rugby league but after you have 12 months of success that's how you build your reputation."
Kidwell has had difficulty assembling the World Cup line-up and was knocked back by Warriors assistant Stacey Jones, who is concentrating on his role at the struggling NRL club, but settled on a line-up that brings a blend of experience and an understanding of current trends.
Renowned NRL administrator Shane Richardson will be the campaign manager for the Kiwis having started with the side in this year's ill-fated mid-year test where senior players Jesse Bromwich and Kevin Proctor were caught up in a drugs scandal and stood down from the World Cup.
The World Cup runs October 27-December 2 in Australia, New Zealand and Papua New Guinea.