Didn't realize that you were preparing these for a recording project! Should be a good one. Let us know when it is available
Some thoughts (sorry they're out of order):
Dr. Gradus: Effervescent and sparkling, great fun. In m. 1 and similar places, the RH is often a little early on the beat, with the result that the fourth note in each group of 16ths and the first note in the next group are compressed together.
Little Shepherd: Why did you choose to have so little pedal here? It seems very atypical for Debussy. Not that you must always soak Debussy in 100% pedal all the time, but this sounds almost more like a Haydn adagio and I'm not convinced it's appropriate for the piece. It sounds rather dry and thin. I would love to hear your reasoning though, esp. since you've studied many of the Preludes with great teachers and this is similar writing to Des pas sur la neige or La fille aux cheveux de lin in terms of sparse line/occasional deep chords.
Golliwog: The dance rhythm and feel are perfect! You have a nice range of approaches to the different sections, from more vibrant to more subdued. The Tristan und Isolde section is handled with refinement but still a pleasant and conversational humor. The ending is very energetic and satisfying.
Snow is Dancing: You could use a lot more rubato if you wanted (think of the wind gusting and blowing the snowflakes around), but it's not necessary. This is really nice picturesque playing.
Serenade: Very well done. Evokes the guitar nicely.
Jimbo: Wow, that's a great elephant. You do have a good feel for characterization.