Lydiate combined playing with coaching duties for Dragons in the 2024-25 season when he made 12 appearances before hanging up his boots.
The 38-year-old former blind-side flanker has stayed on as part of Filo Tiatia’s staff with responsibility for the contact area.
Ex-fly-half Patchell joined Dragons last summer in a part-time role and works with the kickers.
Former Wales prop Jones made 223 appearances for the Ospreys and played in 57 internationals. He was appointed as scrum coach for his hometown side in 2018 before being promoted to first team coach two years later.
Ospreys and Dragons meet in Bridgend on Saturday, 31 January when their Wales contingents will be missing.
There is one round of URC action during the Six Nations with Ospreys hosting Ulster and Dragons entertaining Benetton on Saturday, 28 February.
“Having Duncan, Dan and Rhys return to work alongside Steve, Danny and Matt allows us to maintain a good balance in the coaching team,” said WRU director of rugby and elite performance Dave Reddin.
“That consistency and cohesion will help to continue to grow and develop the playing group.”