Präludium con Fuga D dur, pro Organo pleno

This is the twin prelude to the one I uploaded a few weeks ago. They appear in the same manuscript, Mus 2969-U-500, owned by the Sächsische Landesbibliothek – Staats- und Universitätsbibliothek Dresden. According to the Johann Peter Gesellschaft this prelude has not been published before.
To make a playable score I had to make a few editorial choices. The prelude indicates in a few places “pian.”, but I think that is an error. In my opinion it is more logical to presume that “pedal” is meant. And in a few places accidentals are missing in my opinion.
The fugue is, as is more often the case with Kellner, the weakest part of the piece. Appearantly Kellner meant to write a four or five voice fugue, but allready in the exposition voices are appearing and disappearing at random. After 15 bars of that, Kellner just gives up, and continues in a two part (three near the end) texture, and the music immediately gets a lot better.
It is not clear wether the pedal is supposed to have a part in this fugue. A pedal part is not indicated, but the voices in the exposition are to far apart to be playable by hands alone. Yet, after the 15th bar, the music is just two voices, and can be played with hands alone. Should the pedal re-enter near the end of the fugue? If so: where? As it seems strange to me, to use the pedals only in the first 15 bars of the fugue, I chose to let the pedal voice re-enter in bar 32. But I had to alter the notes a little to make the entrance a bit more plausible.
As usual, I indicated al these editorial choices in the score.

Score available here: http://partitura.org/index.php/johann-peter-kellner-praludium-con-fuga-pro-organo-pleno-d-dur/