well medical is not "required" until case officer asks. usually they don't ask provided the baby is born in Australia. same is with form 80. these are only required if CO asks.
these are supplementary docs. we confirmed with DIAC. the basic requirements are checklist provided on immi website.
rest is your own choice. a lot of immigration agents ask you to prepare a lot of extra docx... but for us simple, easy documentation is the way to go.