Mbeumo and Wissa featured in Brentford's final game before the international break, with the latter scoring a brace in a 3-2 home victory over Bournemouth.
However, Mbeumo and Wissa were unable to feature for their respective countries during the recent international period.
With the pair struggling with knocks, there was some doubt as to whether they would be available for Brentford's trip to Goodison Park.
Brentford receive Mbeumo, Wissa boost
However, Frank has now allayed those injury fears, revealing that Mbeumo and Wissa will both be fit to feature in Saturday's contest.
The Brentford head coach also confirmed that Ethan Pinnock will be available for selection after he sat out Jamaica's recent international fixtures due to a small injury issue.
"All of them I expect to be available and ready," Frank told reporters at Thursday's pre-match press conference.
"All three situations are different minor issues. It's a little bit similar to the last international break when Mikkel Damsgaard and Christian Norgaard were called up for Denmark and did not travel but managed to be ready for the next game.
"Sometimes a week's rest can make all the difference, so I expect them to be ready. We're very thankful for the cooperation from the three national teams."
Pinnock is expected to start in the Brentford backline against Everton, while Mbeumo and Wissa will offer the visitors' main attacking outlets.
Thiago on brink of Premier League debut
Frank also delivered the positive news that club-record signing Igor Thiago is set to feature in a Premier League matchday squad for the very first time.
Thiago has been made to wait for his competitive debut after he sustained a knee injury in a pre-season friendly against Wimbledon in July.
"Thiago is in a good place and trained very well this week," Frank added. "He will be involved in the squad."
However, the Bees are still unable to call upon the services of Kristoffer Ajer, Joshua Dasilva, Gustavo Nunes, Aaron Hickey and Rico Henry.