The BKK to HND F flight is a light on the service levels. It is the exception to the rule that JAL does not light service on red-eye F flights. Though admittedly if they did a full F menu after departure they'd basically leave no sleeping time.

You can probably get them to serve the Japanese breakfast after takeoff as well, but whether there is then a second breakfast before landing is a question of loaded meals and other passengers' choices. But generally yes, after take off it is a la carte.

Not sure what your final destination time zone is, but if it is Japan, this flight would, in my opinion, be great to get some sleep and more adjusted to Japan time.