The young Reds will find out their opponents in the group stages of the competition on Thursday, with the Youth League's pool phase replicating that of the Champions League.
And, as was the case in 2018-19, U18s boss Lewtas will be in charge with U23s manager Critchley acting as his No.2.
The 32 sides entering via their club's first team's involvement in the Champions League will compete in groups with the same teams and fixture list as the senior tournament.
The eight group winners will progress automatically to the round of 16. The eight runners-up will go into the play-offs along with the eight sides to advance through two knockout ties from the 32 domestic champions entrants.
The knockout phase of the Youth League will consist of single-leg ties, with the semi-finals and final scheduled to take place on April 17 and 20, 2020, in Nyon, Switzerland.
Last season, Liverpool reached the last 16 before being knocked out by Dinamo Zagreb following a penalty shootout.