Why is Lukas a typo? It's a name
This is a Pearson sentence ( https://www.duolingo.com/comment/24066422 ).
For some reason, some of the alternatives list "Luke, Lucas, Lucas" as three options rather than "Luke, Lukas, Lucas". It seems like a mistake to me.
Report it if you'd like.
Is "Menschen" pronounced the same way as "Mädchen"? The two words sound very similar in when speaking...
No, not the same.
Menschen has a short e in the first syllable and Mädchen a long ä; also, n and d sound different as do sch and ch (at least in the standard language).