The first photo shows some lerps and what I assume is a psylid nymph. Psylid nymphs except for the first stage crawlers should not normally be seen but I read that sometimes they move to a different location to feed, which would make sense since the leaf seems to be quite badly damaged. Other photos show what appear to be newly emerged adults on the same red gum sapling. I assume the orange ones (about 2mm long) are female and the tiny black ones (about 0.5mm) male, but this is just a guess they could be something completely different. There were masses of lerps on this sapling and most still had nymphs in them when the photos were taken
Female galls on Yellow Box. Counted at least 40 on a 2m high sapling. Almost all straight sided, just a few more bulbous. The longest was 20mm. Bulbous gall in the photo is 16mm long and about 6mm diameter.
Colony of Red-line Gumtree Hoppers at the base of a ca. 7 year old Yellow Box (approx 10cm trunk diameter). There were also a few individuals and pairs dispersed on a low branch. There were no ants in attendance so it appears the bugs are not feeding, but they must be at least preparing to mate. The male in the second photo is holding onto the female with his middle legs while vibrating his front and backs legs, usually not touching the female. Many pairs in the main group were behaving in a similar way with varying degrees of contact. In one pair the male had his hind legs stationary but was stroking the "face" of the female with his front legs.
Seems to be feeding on a Yellow Box leaf. After wading through 500+ Pentatomidae photos on Bowerbird the only match I could find was http://www.bowerbird.org.au/observations/88269. According to the post Acanthosomatidae differs from Pentatomidae in having 2 instead of 3 tarsal segments but I don't think you can see that in my crappy photo.
Another Gumtree hopper seen last summer on Eucalyptus melliodora but not this summer. I have said genus Eurymeloides due to the two rows of spurs on the hind tibia (see third photo), but does not match any species pictures I can find.