I'm not sure where I got this idea from.. possibly from erroraeneous IDs online. I've had a look at the nymphs in A Guide to Australian Grasshoppers and Locusts Rentz to familiarise myself a bit more.
Yes, but you need to check if it has a prosternal peg between the front legs ( Oxyinae and Catantopinae, including Bermius) or not (Acridinae, including Caledia).
I will have to go through past id's to check and reassign if necessary,