The three problems:
Bar between measures 23 and 24 has been omitted. This is likely in error as edition  separates these measures. However, it could affect problem #2.
Rhythm of measure 24. The notation is quite vague so there are two interpretations, three counting recordings I've found on youtube, and a final, improbable, suggestion.
- There are six groupings of notes, 48/32 (48 notes where there would normal be 32 sixty-fourths). This is equivalent to 3/2 (triplets); therefore there are 12 notes per quarter-measure. The last group - of six notes - is therefore played slower. I find this to be most elegant, on paper.
- There are 11 groupings of notes, 44/32. This is equivalent to 11/8; therefore there are 11 notes per quarter-measure. The last group - of six notes - is therefore played faster. This is very messy.
- There are 46 notes in a measure to be played in equal tempo; therefore a 46/32 tuplet. Aesthetically, I prefer recordings in this style.
- Though quite unlikely, it is possible the missing bar of  was intended to split measure 24. This would explain why, unlike in subsequent measures, there is no tuple notation - the notes are in fact not tuples.
All recordings I've found either fall into [2.3] - equal tempo or [2.1] - slowing for the last six notes. I should also point out that I'm not sure what meaning, if any, the particular style of beaming - groups of four beamed into groups of 8 - in measure 24 is intended to convey.
Notation "Mesuré" (meaning even or equal) in measure 25 is ambiguous:
- "Mesuré" refers to the melody and thus the tempo; the arpeggios in the upper staff are of varying velocity.
- "Mesuré" refers to the arpeggios in the upper staff; the melody and tempo therefore vary to match.
Once again, recordings fall into both categories, though predominantly biased towards [3.2].
I'm not sure how to practice this piece with these uncertainties. While I prefer an even arpeggiation (2.3 and 3.2), I don't want a musically incorrect (or inaccurate) performance. I do not know if Debussy required a strict interpretation of his music but I doubt it, given the ambiguous notation and the "rubato" tempo indication. Nonetheless I'm asking here: what should I do?