Offences as a minor

I've received the Australian Federal Police check for my husband and I am slightly worried. I knew that he had had a pretty rough time as a teenager but seeing it all in front of me is a bit disconcerting. Like usual, getting any sort of answer from immigration at the Sydney office is like cleaning fingernails with a pencil and none of my emails have been answered. I am at a loss. If anyone could give me any information, that would be fantastic.

He has some convictions as a minor. He was not actually convicted for any of these but he was fined, ordered to pay compensation and had to perform community service. Am I correct in thinking that offences as a juvenile do not make one criminally inadmissible or will this automatically have him rejected? I looked on the application for rehabilitation form and it asks for documents proving that Australia has a child court system/young offenders act. Is this still necessary considering I am sending this to Sydney? Surely they would know that Australia does have this...if I do have to send it, what sort of document are they looking for to prove this?

I have looked around but to be honest...it all seems like a jumbled mess to me. Any assistance would be greatly appreciated.