The fact that you are accessing BIOS using HDMI cable, seems to be a problem with Display Port cable, not the graphics controller.
Try testing graphics driver provided by Asus here: http://www.asus.com/us/Motherboards/Z87IDELUXE/HelpDesk_Download/
Thanks for your reply Allen,
Apparently my issue #1 is a known POST issue with 4K monitors (according to Robert_U from intel) and is unrelated to the Windows Drivers (which don't get loaded until after Windows launches anyway). My DisplayPort cable works perfectly in all other scenarios once windows is loaded. Supposedly there is a VBIOS update that must be applied to the SBIOS by the OEM to address this.
WRT #2, This appears to be more related to the intel windows HD graphics driver, but there might also be a connection to the VBIOS issue in that it only happens with the 4K DisplayPort 1.2/60hz connection (4K HDMI 30Hz has no blanking issue).
Any further thoughts?