So I haven’t used UDK in a few years but I remember that there was a really helpful volume that you could place and it would cut holes in things. Is there a preset volume like that in UE4 or do I need to use visibility?
As far as I know, there isn’t a similar volume in UE4. If you wish to cut into terrain in particular, however, there are a couple of methods for doing that, including setting up a material to mask out visibility and collision Landscape Materials | Unreal Engine Documentation
Yes. You can create a bsp object and turn the box whatever you want within options