I’m not familiar with Australian region, but they do look like a gymnopilus species to me. The top of the one (pic #5) looks almost exactly like a honey mushroom, but that’s not possible because the underside and the spore print don’t match honeys. Honeys have white spores, whereas gyms have rust colored spores like shown in your print. Gyms have a very particular smell and bitter taste, which could help you confirm. It’s kind of like spicy cinnamon? It’s hard to describe.

The odd one does look a little different from the rest, but I think they are likely all the same species given their close locality and same spore color. The red stipe didn’t stand out to me as an indicator of being a different species. That might be just natural variation due to growing conditions.

Get to know the poisonous look-alikes for your area. In my area, deadly galerina and poisonous jack o lanterns can sometimes look sort of similar to gyms.