Mekies said: "The appointments of Tim, Guillaume and Alan add a vast amount of winning expertise to the team, and I have no doubt that they will help take the team to the next level in F1.
"We already have a very strong and hugely experienced group at the team and bringing onboard highly skilled individuals like Tim, Guillaume and Alan will boost our capability and help us meet the highest technical standards, both at the factory and at the track."
Guillaume Catellani joins from Red Bull's senior team as deputy technical director.
Goss spent 28 years at McLaren until losing his job in 2018 as the team went through a restructure following a loss of performance.
He said: "There's an exciting challenge ahead of us but I think the team is well-equipped to meet that head on."
The 60-year-old heads the team's technical department and will oversee technical director Jody Eggington, with Catellani next in seniority.
Permane had been at Renault in its various guises for 34 years when he became the victim of a management reshuffle in the middle of last season, which also saw team principal Otmar Szafanauer lose his job and chief technical officer Pat Fry choose to move to Williams.
A widely respected figure in F1, Permane's move amounts to a promotion from his former position at Renault.
He said: "After a few months of downtime, it's great to return to racing again.
"From long experience, I know how professional, driven and competitive the people within this race team are and I can't wait to see where that spirit can take the team in the future."