I think you are right about the Australorp and RIR, but I don't know about the third peep - I can't really tell from the picture - what kind of comb does she have? Yes, my Australorp chicks are a little bigger than the others, too.
Is a production red the same as a red star? I have a list from MM, because I ordered the brown egg layer mix I have these to pick from as far as what they could be.
Black Australorps; Lt. Brahmas; Dark Cornish; Black and White Giants; Buff and White Orpingtons; New Hampshire, Rhode Island Reds, Barred, White, Partridge, Buff Rocks;Delaware, Sussex, Turkens; White, Silver Laced, & Columbian Wyandottes, Red Star and Black Star.
I am going to try to put pics of each kind I have on my page sometime today so maybe I can find out what they are, I would just like to be more sure of myself. I have read enough that I know I need to show the legs and comb...