I don't know about the other plants but I think the rose looks dry. The green worms are rose slugs (sawfly larva) and they are a real pest. There are sprays for them but I have no idea what might be available in Australia. I will say that we don't usually recommend those combo sprays as they are never full strength and tend to not be as effective. The only other method is to hand pick them off. That is tedious but very effective. There are also fungal sprays that will take care of rust but again I'm not familiar with brands in Australia. Make sure you find one that says specifically for rust. It will protect new growth and any leaves not infected yet but any existing rust infection on leaves will remain. Most fungicides are a preventive NOT a cure.
A good rule of thumb is to only spray for insects when you see them and have properly identified them using the appropriate spray for that insect. For diseases you can spray BEFORE you see symptoms to prevent an outbreak.
