Coach Clark Laidlaw said the return of prop Lomax and hooker Aumua is a boost. They suffered tricky injuries, and their return was not easy.
"They need to be able to maul and scrum, so the loading and the reintegration of that sometimes takes a bit longer. But they're back up to speed. There's a real energy with those two.
"It's nice to have Asafo back in the team. He has a demanding nature around the group and you can feel guys respond to that."
Lomax said he was looking forward to the start against a good pack.
"They're physical, they try to play through the middle of you. They have a good set piece. We've had pretty good competition in the front row, some of the boys are playing good rugby and it's up to us to go out there and perform."
Lomax said the injury he has recovered from had been about since Super Rugby Pacific last year.
"I played through it a little too long and it's taken longer to recover."
Being unable to play had reinforced how much he missed playing, and he felt confident and back to normal after coming off the bench for a stint against the Highlanders.
Laidlaw said the side is focused on preparing to face a good Waratahs side.
"We're under no illusions. It's a Wallaby front row, a Wallaby pack, who have won four and lost one. We've put a lot of energy and attention into playing them this week."
Laidlaw said the bye was an ideal junction to recharge and reinvigorate the squad, who returned with energy and purpose to play the Waratahs.
However, there was also confirmation that first five-eighths Harry Godfrey faces six weeks out due to a lower leg stress reaction suffered against the Highlanders. Laidlaw confirmed that centre Billy Proctor would likely be another six weeks before returning.
Riley Hohepa will start at first five-eighths, and Laidlaw said he has prepared well for the opportunity.
"He's a more mature player. He's calm; he's led the week well. He understands how we're trying to play the game.
"One of the things we reflected on during the bye week is how we got more rhythm in our attack. We can see the space [in review]; we've got to be way better at seeing it during games and moving the ball to that space.
"All we went him to do is keep facilitating the game for others and we think he can do that well."
The loose forward combination is slightly changed, with Brayden Iose playing on the blindside flank alongside open flanker Du'Plessis Kirifi and No8 Peter Lakai.
"It's an opportunity for Brayden to start alongside the other two. The mix of those three is always important and Brad [Shields] can add something later in the game. It's an opportunity for Brayden to play a slightly different role that might give him a bit more space in the game and to see how that looks."