I couldn't help but notice a few problems here...
- Professor Layton is not one of the Layton Brothers.
- In fact, one of the Layton Brothers is a girl.
- There are no Professor Layton characters anywhere in this game, even though it's supposed to be a Professor Layton spinoff.
EDIT: Japanese readers have informed me that Englebert and Luigi are not Professor Layton's siblings. Instead, they say that Englebert is supposed to be Professor Layton's son. So...Layton has a son we've never heard about before. Ditto for Englebert's unknown mother. Oh my. Layton's family tree just got immensely more complicated.