Gibbons placed 11th overall in January’s Tour Down Under and followed that up with a fourth position at the Cadel Evans Great Ocean Road Race.
He also twice finished in the top-10 on Giro d’Italia stages and won the individual time-trial at the African Games this year.
“I’m very pleased to be continuing my journey with Team DD as we change to Team NTT for next season,” said Gibbons.
“I’m looking forward to more opportunities next year and to building on some of the results achieved this year.”
Dlamini took the step up as a neo-pro last year after riding for DiData’s continental team and is currently riding his debut Grand Tour, the Vuelta a Espana.
“I’m really happy to be given another opportunity to continue living my dream and to step up into the big league,” he said.
“This year has been a year of ups and downs but I’ve learnt a huge amount. Next year I want to be a totally different rider, now that I’ve got the depth through experiences like the Vuelta.
“I’ve got great ambitions for next year along with the team, and look forward to going bigger and better.”
Thomson will ride for the outfit for an eighth season next year. He has been a key rider with his all-round ability and has proved a huge asset on and off the bike.
“I’m super happy to sign for another year to make it my eighth season in a row. I’m incredibly happy to have a home here and very motivated to make 2020 the best of them all.”
Eritrean Amanuel Ghebreighzabhier, Italian Enrico Gasparotto and American Ben King have also renewed their contracts.
Team principal Douglas Ryder said he was thrilled to confirm that “this talented group” had committed their immediate futures to the team.
“We continue to provide the platform, via our continental feeder team, for some of the very best talent from Africa to get the opportunity to showcase their abilities on the biggest stage.
“Considering how the likes of Ryan, Nic and Amanuel have come on in the last two years the future looks very bright.
“In Enrico, Jay and Ben we have slightly older heads who are going to continue to provide not only versatility and solidity to our group, but also showcase that one of the true strengths of this team is its diversity.”