PXE stands for Preboot Execution Environment and is a client-server interface that makes it possible for computers to be booted from a remote server on a network. This makes it possible for you to ...
VirtualBox is software that runs on Windows, OS X, Linux, and Solaris, capable of full virtualization. Full virtualization allows VirtualBox to run OSes entirely different than the OS it is running on ...
I don't think Virtualbox has a UEFI option, so I think virtualbox is (rightly) booting legacy. But still it can't boot from that ISO I just tried VMWare Player I notice that one can choose UEFI or not ...