You won't be able to install via usb because refit/efi won't enable usb booting. You can use the internal dvd drive for installation however -- or replace the drive with a hard drive containing the installation medium.
Best way to do this is to partition your first drive into 3 partitions before installing OSX using disk utility pre-installation. Install OSX, bootcamp, windows, then linux. Then you're free to remove your dvd drive if you prefer using a hard drive in that bay, but you'll need the drive for OS installations.
Best way to do this is to partition your first drive into 3 partitions before installing OSX using disk utility pre-installation. Install OSX, bootcamp, windows, then linux. Then you're free to remove your dvd drive if you prefer using a hard drive in that bay, but you'll need the drive for OS installations.