Hi there Nick and welcome to the forum .
The first photo is definitely a young Green and Golden bell frog (Litoria aurea) possibly male but not completely sure. The second looks to be also a Green and Golden Bell frog but the third photo is definitely a Southern Bell frog (Litoria raniformis) The forth photo looks like A Green and Golden but not 100% sure. I would suggest separating Bud as he is small and possibly could end up as lunch for one of the other larger frogs. The tadpoles are safe for now but once morphed they will also be lunch. Unfortunately you will also have to separate the Southern bell from the Green and Golden's as it's not a good idea to mix species and can be fatal. If you are able to take another photo of the last frog from the top view so I can confirm species or you. I hope this has helped