What is the minimum pedal keyboard compass needed to play ALL of J.S. Bach's pipe organ music?

Question

Simple straightforward question: What is the minimum pedal keyboard range needed to play ALL of J.S. Bach's pipe organ music?

Optional ways to embellish the answer:

1. Did Bach ever write a piece for which the organs he had at his disposal at the time (let's say during his time at Weimar, 1708-1717) did NOT have sufficient range? One example:

   • (Thanks to @KilianFoth for the finding) Fantasia in G major, BWV 572 (score here) has a B that is a semitone lower than the lowest C (measure 94). How would an organist play that note since most organ pedal keyboards, even today, start with C? An ingenious solution is for an assistant (who already helps with page turning, etc.) to pull a 32' stop just for that note, as clearly seen in this performance (minute 3:50). The stop used in the organ at St. Catherine's, Hamburg is the Groß-Posaune 32'. In this audio-only performance (minute 3:41) on the Trost organ, Waltershausen, the organist probably used the same trick since he listed the pedal registration he used without the 32' stop but the organ does have a Posaunen-Bass 32'. But if the organ doesn't have a 32' stop (such as the Vater-Müller organ, Oude Kerk, Amsterdam), then the organist would need to play that B an octave higher (minute 3:50).
   • This article (thanks to @phoog) has more discussion about that "impossible B" along with other "impossible" notes Bach wrote.

2. Which organ pieces require a pedal keyboard beyond 2 octaves, assuming the lowest note is C? An interesting etude for pedal by Bach is Pedal Exercitium (BWV 598, in G minor, critical edition score here) which calls for exactly 2 octaves (C-c¹) but purposefully left unfinished in the dominant. So organists provide their own extension to make the piece ends satisfactorily in G minor, who usually add more notes beyond the highest c¹:

   • Käthe Wright Kaufman's extension takes it to d¹. See her performance in this video (minute 3:45-5:42, after introducing pianists to organ pedal technique, organ shoes, and how this piece was possibly inspired by Bach's own Cello Suite No. 1 Prelude).
   • Matthias Havinga's extension takes it to f¹. See the discussion of his extension (score of his extension at 0:55, and how he composed it so it naturally leads as a prelude to Bach's Fantasia and Fugue in G Minor, BWV 542) and his performance for the Netherlands Bach Society "All of Bach" project.

Answer 1

To play ALL of Bach's music, you'll need a 30-pedal pedalboard (bottom C to F above mid-C). The top F is, as far as I'm aware, the highest pedal note needed for Bach's music (BWV 540 uses the whole range from low C to top F in one glorious pedal solo).

Although, as has been mentioned in the comment, if you want to play all of Bach exactly as (it is thought) he wrote it, you'll want to extend your pedalboard down by one note (B below bottom C) to play the Fantasia in G major, BWV 572, where he inexplicably goes below the range of any organ available back in his day. This has now been solved by Cameron Carpenter in the digital organ he had custom-built for his concert tours (although good luck getting your hands on that!). Other recorded methods of dealing with this are a) play the whole movement a semitone up, or b) just play it up the octave.