Welcome Aussies!
Spain definitely celebrates Semana Santa! Many shops and bars will probably be closed 1/2 day on Good Friday and throughout the weekend...so be aware you may be liimited in what you can buy in terms of provisions. I believe the majority of albergues will be open.
It just requires a little extra preparation, and if you are aware of it, you don't get caught short or disappointed. It is similar to regular weekend closings, just longer, and with more celebrations!
Buen Camino,