In a seismic Monday night for Maroons State of Origin officials, Smith first pulled out of the running.
The champion hooker had been the early frontrunner to replace Slater, who had publicly backed him to do a "fantastic job" if handed the job.
Queensland captain Cameron Munster and Wayne Bennett had also endorsed Smith as the man to take over, before the 43-year-old ruled himself out of the role.
But a little over 24 hours later, the state's most-capped player said it was not the time for him to take on a head-coaching role at the Maroons.
"I've heard comments from Wayne Bennett (endorsing me) and I really appreciate the sentiments, but it's not the role for me at this current time," Smith said on Nine's 100% Footy.
"I was lucky enough to be involved in the camp with the players and Billy when he started in 2022 and '23 and thoroughly enjoyed my time.
"But there was a reason I stepped away after 2023. I couldn't fully commit to the role and at the time that was an assistant coach, not head coach.
"And nothing in my life has changed."
There had also been conjecture that Walters could stand down from his post as Australia's Test coach after the World Cup and return to the Maroons.
Walters coached Queensland to two series wins during his stint in charge between 2016 and 2019 and would have had arguably the best resume of all candidates.
But he too confirmed to News Corp on Monday night he would not be taking on the Maroons job, vowing to honour his two-year deal as Kangaroos coach.
That leaves Queensland officials with a search for Slater's replacement.
Ballin now shapes as a likely frontrunner, having served as Slater's assistant since 2023.
The 42-year-old played an Origin for the Maroons in 2010 and was a leading option for the full-time job at Manly this year before Kieran Foran's hot start.
He has been on Brisbane's staff since 2021, and is highly regarded in Queensland.
Te'o has also served as an assistant to Slater and had held a similar role to Ballin on Brisbane's staff before his high-profile exit earlier this year.
The back-rower played seven games for Queensland between 2012 and 2014, and was in charge of the Broncos' defence through last year's premiership run.
Slater's other key member of staff, Johnathan Thurston, has already ruled himself out of the running.
Josh Hannay is another who long served on the Maroons coaching staff, but it is understood Gold Coast would be unlikely to allow him to juggle Titans and Queensland duties.
Anthony Seibold has also spent time as a Maroons assistant and could shape as another option.
