The pair have been ruled out of the quarter-final at Lucas Moripe Stadium through injury.
Bafana Bafana international Wana was bought from relegated Moroka Swallows in the off-season, while Mhango netted five League goals for Phunya Sele Sele last term after scoring nine in his maiden PSL campaign.
Larsen told Celtic's website: “Except for Gabadinho Mhango and Vuyisile Wana who are out of injuries, we have a clean bill of health and everyone is raring to go. I must concede though, it takes time for the players to gel but we are steadily getting there.”
He added: “We are equally ready to fight and ultimately win the trophy for our loyal supporters. Our current squad is full of quality players and they all want to win the trophy.
“Sundowns is a quality side but our hunger and determination will see us through. Our players are yearning for glory. We have done our home work, studying their weakness while trying to improve on our strengths.”
The match kicks off at 19h30, as does holders Kaizer Chiefs' tie with Maritzburg United at FNB Stadium.
Bidvest Wits and Ajax Cape Town advanced to the semi-finals of the event on Tuesday with respective victories over SuperSport United and Orlando Pirates.