All three veterans are non-roster invitees who were in camp on Minor League contracts. The three had a deadline of noon Tuesday to be notified of their status.
Kotchman will be the Marlins' Opening Day first baseman, while Kearns will be a right-handed bat off the bench. Qualls, a right-hander, will join the bullpen.
"We had to let them know that they will be on the Opening Day roster," manager Mike Redmond said. "Those guys will be added."
After making seven roster moves on Tuesday, the Marlins are down to 32 in camp. They will need to be at 25 by Sunday, with Opening Day at Washington set for 1 p.m. ET Monday.
Of the 32, Miami is expected to place five on the disabled list -- Jeff Mathis, Logan Morrison, Alfredo Silverio, Jose Ceda and Joe Mahoney.
The rotation is set, and it will be -- in order -- Ricky Nolasco, Nathan Eovaldi, Wade LeBlanc, Henderson Alvarez and Kevin Slowey.
Redmond said a decision still must be made regarding one bullpen spot.
The relievers still in camp are closer Steve Cishek, Jon Rauch, Ryan Webb, Mike Dunn, Qualls, A.J. Ramos and John Maine.
Rob Brantly and Kyle Skipworth are the two catchers.
The starting infield projects with Kotchman at first base, Donovan Solano (second base), Adeiny Hechavarria (shortstop) and Placido Polanco (third base).
Non-roster invitees Wilson Valdez and Chris Valaika are vying for the utility infield spot.
Veteran Greg Dobbs will be the primary left-handed bat off the bench.
It appears five outfielders will be kept -- Juan Pierre, Giancarlo Stanton, Justin Ruggiano, Chris Coghlan and Gorkys Hernandez.
Matt Diaz has signed a Minor League deal, and the plan is to keep him at Triple-A for now to give him at-bats and playing time. But he could be an option to be on the roster after the season starts.