I called CX today and as expected, they fooled me around for a while before answering my specific question. They said all specialty meals would be the same regardless which cabin you are seated. I also checked with a friend who used to run CX catering, she also said the same, while J kids meal might just get a few more snacks and goodies. Given my flight will be a short haul one, may be I should give it a try.
As said, CX’s call centre is such a horror given most are rather green.