@Mark.1 yes start gathering documents, family & I already did our medicals but the validity is only 12 months, less worries as we're onshore applicants.
PS I read here somewhere that they also can cut the validity 1/2 months if there's health waiver or something. If you're outside Australia, you have to be smart calculating the best time to obtain both of these kasi I reckon they calculate Initial Entry Date based on the expiry of one of these.