Both players completed 70 minutes as the Owls hammered Harrogate Town 4-0 at Hillsborough to ensure they topped their group in the Papa John’s Trophy and guaranteed themselves a home tie in the last 32.
Byers, who had been out since September with a groin injury, grabbed Wednesday’s second goal of the game with a well-taken header in the second half following Olamide Shodipo’s pinpoint cross.
Luongo made his first start since August, having been sidelined by a hamstring injury.
“I thought them two can feel really pleased with their outing,” Owls boss Darren Moore said post-match.
“We feel now, in terms of the minutes they have got and hopefully if they come through the game unscathed in the next 24 hours that means they will then be looking to be added back into the squad (for Gillingham).
"The importing thing was that nobody got injured and all the players who played specific minutes played the specific minutes.”
Byers added: “It’s been frustrating but I have turned a corner now and hopefully I can stay fit for the rest of the season.
"I felt good in the game, it was probably the right time for me to come off but I really enjoyed it tonight.”
Moore described Tuesday as ‘the perfect night’ for his team, who kept a third successive clean sheet despite a makeshift starting XI featuring 10 changes from Sunday’s draw against Plymouth Argyle.
He also handed a debut to David Agbontohoma with fellow youngsters Liam Waldock and Ciaran Brennan featuring for 90 minutes after returning from their recent loan spells in non-league.
Young forward Korede Adedoyin emerged from the bench to win and convert a penalty late on for the Owls’ fourth goal.
Moore said: “They play Under-23s football but eventually you have got to thrust them onto the front line and I thought it was the right game for them tonight.
"I thought as the game went on they grew. Liam Waldock settled down more, Ciaran Brennan started to find his range of passes. All three of them in the magnitude of the game it was were really pleasing.”