I've flown JQ (or Sh*itstar) a couple of times and it wasn't any way nice experience.
You do get a meal and entertainment with your AY Y codeshare but no lounge access and no seat selection. Even 787 feel really cramped (because they are) and narrowbodies are even worse.
But HEL-KIX-CNS is probably the easiest way to go and see the Great Barrier Reef