The Dolphins extended Selwyn Cobbo until 2031, while Kulikefu Finefeuiaki and Hamiso Tabuai-Fidow are contracted until 2029.
Retaining Herbie Farnworth before his current deal expires remains a major priority.
Forward Sebastian Su'a is poised to sign a multi-year extension through the end of the decade.
He joined the Dolphins in 2025 after Newcastle released him in a player swap for Mason Teague.
Assistant Rory Kostjasyn helped sign Su'a, the New Zealand rugby union prospect he previously coached at Newcastle.
The 23-year-old, who stands 198 centimetres, made one NRL appearance: 18 minutes against Newcastle in a one-point loss.
Rival clubs viewed him as a potential target when the November 1 contract window opened.
Across 15 Queensland Cup games for the Redcliffe Dolphins, Su'a averaged 114.4 running metres and 50.4 post-contact metres per match.
He also made 27 tackle breaks, 17 offloads and 22 tackles per game, with 94.3 per cent efficiency.
Redcliffe finished second, won the premiership and beat Penrith 68-14 in the State Championship.