Chong, 19, and Garner, 17, were named in United's travelling squads by Solskjaer against Newcastle and Cardiff but failed to make the matchday 18.
Garner and Chong both started matches in United's pre-season tour draw with San Jose Earthquakes in the United States. Chong enjoyed cameos against Liverpool and Club America while Garner emerged in the win over Real Madrid.
"We're about wining trophies and the FA Cup final is such a fantastic one to play in," Solskjaer said. "I played in the 1999 one at Wembley and after having watched so many FA Cup finals as a kid, to be able to walk from the dressing room and up to the pitch was fantastic. I've seen so many times in Norway.
"And that's what we hope for, get to the final. Whatever competition you're in, you want to win at a club like this and you expect, if not to win it, that's more or less what you expect from a club like this and players we've got."
Confirmed United squad members vs Reading:
Sergio Romero, Lee Grant, Diogo Dalot, Ashley Young, Phil Jones, Victor Lindelof, Matteo Darmian, Luke Shaw, James Garner, Scott McTominay, Andreas Pereira, Marouane Fellaini, Fred, Juan Mata, Alexis Sanchez, Tahith Chong, Marcus Rashford, Romelu Lukaku, Anthony Martial