Dembele missed Saturday's 4-0 DFB-Pokal win over Rielasingen-Arlen after being suspended by the club for skipping training earlier in the week.
Lewandowski scored a deflected free-kick, with Kingsley Coman firing home a second before a Lewandowski tap-in. Lewandowski grabbed his second on the hour mark, tapping in from close range after fine work from record signing Corentin Tolisso, before being replaced by the returning Arjen Robben on 63 minutes.
Bayern won a free-kick on the edge of the box in the 79th minute, and whilst the players stood over the ball, Ribery can clearly be seen untying the shoelaces of referee Bibiana Steinhaus!
Officiating in her first Bayern game, Federation Internationale de Football Association referee Bibiana Steinhaus, 38, enjoyed an untroubled afternoon in eastern Germany as the record cup winners cruised into the next round.
"It's always important to score the first goal, and it's not always easy. We didn't have much space today, Chemnitz played defensively".
The visitors opened the scoring through Marc Bartra in the 12th minute, before Aubameyang doubled the lead from the penalty spot in the 41st minute. "We did exactly what we had planned and what we had to do to get into the next round". Aubameyang claimed his second in typical fashion after the break, accelerating away from two defenders before finishing with a chip over the goalkeeper. "In the second half, we have created more opportunities from which we scored the goals".
Yoshinori Muto scored twice as Mainz won at fourth-tier Lueneburger SK Hansa 3-1 while Cologne beat fifth-tier Leher TS 5-0.
Darmstadt, relegated from the top flight last season, fell 3-1 to Jahn Regensburg, recently promoted to the second tier.
There were also 4-0 wins for second-division sides Heidenheim and Kaiserslautern.
Information from the Associated Press was used in this report.