Which Linux distro are you going to install? Linux doesn't use ntfs. You'll want to delete the extra partition and just leave it empty. Boot into your Linux installer and there should be an "Install along side Windows" option. Then select the empty space and it should handle the rest.
No, BIOS doesn't recognize partitions
When you select a hard drive the boot process get's handed off to the boot loader on the hard drive. When you install a Linux distro it will install the grub boot loader which will allow you to select either Windows or Linux to boot up
It can be added using uefiedit. Which is relatively trivial