Yep. Exactly. There's a few major unanswered family-related questions which will undoubtedly be major revelations, imo. (Slightly spoiler-ish below if you haven't seen S1. Avoid the big spoiler if you haven't watched.)
Who really is Boris Niewald? (aka Alexander Tiedemann)
Who is Peter Doppler's mother?
Who is Regina's father? (Possibly Tronte? Making her Ulrich's half-sister, S1E5: Mikkel's aunt, and Jonas' great aunt.)
Who is/was Agnes Nielsen's grandmother?
Who is Hannah's mother? (Unless I'm mistaken, this hasn't really been hinted at or discussed in the show at all, which is interesting.)
I'd guess that most, if not all of these, will have to do with the travelers.