I have read through this forum with great interest and thank any of you.advance... I'm sorry if this question has been raised before, but I am totally confused !!! On some lines, like Rome to Florence, ES* is about the only choice.
For Krakow to Warsaw, you don't need a reservation, especially at that time of year. Warsaw to Prague shouldn't be necessary either, unless you plan to take a night train .
If they knew enough to recommend you purchase passes, they should know which ones will need reservations, and how to obtain them in Australia.
It really depends on when you're travelling, and which trains you decide to take.
I would suggest you check with your travel agent and/or for those journeys.
If you are coming all the way from Australia, at least make sure your schedule is flexible enough to allow for taking trains after the ones you might have selected. Checking the Warsaw-Prague run on bahn.de, I see that reservations ARE required on virtually every train.
With your point to point tickets, reservations are usually already included. I will try the different websites you have provided and see what details they give regarding whether or not reservations need to be made. Sam, I wanted to confirm whether you have already bought your Railpasses?