The major differecne you will find here in Poke Craft - Catch 'Em All is that there are no normal spawning Minecraft monsters. As a matter of fact the only place you will come across Minecraft monsters are in dungeons. However, no receipe in here require any mob drops and those that do have alternative means to aquire the items.

Also note however that events may occur in the server that spawn monsters on you. This means you will still need protection and a weapon. However, as indicated above you will not find monsters naturally spawning.