Openside James Lentjes and No 8 Luke Whitelock, who along with lock Tom Franklin and cult figure Marty Banks cleaned up at the Highlanders' award evening, complete the trio.
"We've got all our loose forwards back for the first time this year so he's [Dixon] under a little bit of pressure being underdone and the other guys are playing well," Brown said.
Squire was in consideration for the third deciding Lions test. But having now sat idle for two months, his aggressive approach should add another dimension to the Highlanders pack.
"He'll be a bit rusty around game fitness but the way he plays and the way he inspires our team it's just going to be great to have him on the field. We're not expecting him to light it up.
"If the All Blacks had won the second test he might have got a run but with the extra pressure of the series being tied 1-all and with him not having played for eight weeks it was probably a bit risky for the All Blacks to throw him out there."
Brown tipped Sopoaga to stamp his authority after battling a 10-week hamstring complaint and then sitting in the stands for the Lions test series behind Beauden Barrett and Aaron Cruden. With Cruden set to depart to France after the Chiefs campaign, the door is open for Sopoaga to move up the All Blacks ranks.
"He's had a tough year picking up injuries and one that you can't do a lot on. He was a little bit rusty when he came back but he's a had a solid six weeks now so we're looking for him to really light it up against the Reds."
Elsewhere rugged lock Jackson Hemopo has been rewarded for his strong form against the Lions with another start.
The Highlanders will play either the Crusaders or Lions away from home in the quarterfinals but their fate rests more with the results of other fixtures than their own.
Regardless, Brown wants his men to set the tone for what's to come in regards to execution and attitude. Do that, and the Reds can expect another torrid night.
"We will plan for both scenarios. We would rather take on the Crusaders in Christchurch so we don't have to travel too far but if we have to jump on the plane to South Africa we'll do that on Sunday."
Brown was, meanwhile, reluctant to discuss Waisake Naholo's possible move to the Chiefs next year.
"I haven't talked to Waisake. It's out of my hands."
Highlanders team:
Richard Buckman, Waisake Naholo, Malakai Fekitoa, Rob Thompson, Tevita Li, Lima Sopoaga, Kayne Hammington, Luke Whitelock (CC), James Lentjes, Liam Squire, Tom Franklin, Jackson Hemopo, Siate Tokolahi, Liam Coltman, Daniel Lienert-Brown