"Ach, was ist doch unser Leben" (#169)

16' and 8'

Welt, packe dich" (#168)

This is the third tune so far to mix time signatures.  Previously, there were "Brich entzwey, mein armes Herze" (#111) and "O Jesu, du edle Gabe" (#141).

"Sag', was hilft alle Welt" (#167)

I'm assuming that the title is what's sung to the first musical phrase.  If this is the case, the phrase "alle Welt" is sung to notes of all different pitches (F# G A), giving a sense of that breadth, especially since one note is an accidental.