I shall be traveling with my little child (around 22 months) from HKG to MEL for a overnite flight in J. As my child is holding an infant ticket, could anyone can tell if my child can choose the meal service rather than the bottles of baby meal. Also, if there is empty seat beside, can I put my child there for sleep a while.

Don't know about the first, but this question is a definite yes...presuming the crew likes you. Seen it many times. You just need to make friends with the crew because it's their discretion. I can't imagine why they'd say no unless they didn't like you. I imagine as long as you don't seem entitled and whatnot they'll be very obliging. Even more helpful if they find your kid cute. 22 months is right in that sweet spot where I would expect the crew to get all excited.

i did same thing when my kid was 23mth old. Assuming you aren't too large J seat is JUST wide enough for both to sleep on side-by-side, assuming no spare J seat. (mind u pre-flight the loading showed J9C9D9I9 with redemption seat 24 hours prior, with 60% seats non-selected) so I wouldn't hope for a spare seat.

as per meal service - i don't think they will prepare a children meal (vs infant box) on a infant ticket. however common-sense prevails - for example my child and I shared my own meal, I just asked for extra bread and that was sufficient... if they are REALLY nice you can ask for spare main-dish leftover which might come to her, but don't count on it.

I think I had a extensive thread on this matter, do a search for "2 J seat or 3 econ seat" or something like that... too lazy to search from my end.

CX135 is often very full in all 3 cabins. Theoretically, an infant should not require a seat otherwise he/she has to hold a child ticket, however as said above its at the discretion of the crew whether they allow it