Majestic palms seem very susceptible to all sorts of problems, don't know why, root problems fungi and insects seem to love this group of palms, very poor track record here in the North so makes me think they dislike high humidity or the predominant soil type perhaps?
Having those close up shots of Alans palms makes me think thta the home owners of Brisbane are doing even tougher than I had thought, your dams are almost below 19%!
It is going to take more than one rain event to fix those ills.
Back on thread.... recycled watering under good quality mulch (pray for rain) taking a prioritised approach and don't try to save all your plants (since some of them are not going to make it unless you provide very large repeated doses of water), focus on the ones in best health and the ones that demand less water to start with.