Just going to comment on the theme park choices and Japan.
DisneySea-yes, Tokyo Disneyland-yes, DisneySea over Disneyland. Legoland in Japan is in Nagoya, don't do this! You could probably do Legoland in KL but I think it is probably similarly bad. Probably skip to Singapore from KL for...
I complained about this and they have not handled my complaint very well. But they have given me $600 in vouchers so far but they won't make available the $69 OOL to NRT fare that was advertised to me. My complaint is ongoing.