So many works to pick from the FTCL syllabus indeed

Not sure if you have played much Ravel and/or Debussy in the past. From efficiency and exam perspectives, they are no good. High effort serious practice, but for a small amount of time of wonderful music to be performed. I think that the sound colour and mood shaping will be most difficult, particularly when the grand piano of the exam centre is poorly maintained (often in the case in this part of Asia). Exam fee is very high (again, at least in this part of Asia). Worth to take risk?
Nonetheless, if you think you are capable, then no harm to try a bit first, perhaps its first movement. Also, listen to as much recordings of authoritative Ravel interpreters as possible. You must convince the examiners (at least one of them is a piano expert).
If you cannot quite progress in accordance with your expected timeline, then discard it and find another works. In fact, I assume you should have shortlisted a few works to study.
Having said that, many candidates just follow the choices of their teachers to make up their programmes. I did my FTCL by self-learning, and so I can modify mine whenever I deem necessary. For example, my FTCL programme was originally planned (after I explored 90% of the FTCL syllabus, not to the perfection, but to play them and see if my strengths can fit and my weaknesses can be avoided) and changed...
Bach-Busoni Chaconne + Chopin Andante spianato et grand polonaise + Stravinsky Serenade
Bach Partita No 6 + Hindemith PS No 3 + Grainger In Dahomey
Bach Partita No 6 + Beethoven PS No 31 + Grainger In Dahomey
Bach Partita No 6 or Beethoven PS No 31 + Prokofiev PS No 9
Bach Partita No 6 + Beethoven PS No 31 (final)
Why I did not make Gaspard my choice in the programme? I am in my forties and my fingers aren't as swift as before. Also, my hands aren't very big. My piano (at home) is not a decent grand piano, in fact a not-so-well maintained upright, and I can't explore the variety of sound & tone colours for this work. (I did play Ravel Sonatine for my LT though.)
Good luck!