No difference, if there's an existing extra vga card than the Intel HD graphics is switched off internally besides some ones using Lucid Virtu (Can't find any good reason yet, to do this).
I suppose it's better to install the Realtek hardware driver at first and then followed by the X-Fi software emulation drivers.
Yes, as already stated, the used Realtek Soundchip is already known to Win7 internal drivers.
The firmware is integrated within the GENE Z UEFI BIOS so you can't update it without leaking/reprogramming the BIOS for yourself. As already stated, ASMedia is a 100% ASUS company, so better just wait here for ASUS releasing new drivers / updated firmware with next UEFI BIOS Version. AIDA shows me that mine has the Asmedia 1042 USB3 controller onboard.
Also, regarding the ASMedia USB3.0 chipset on the board; We can't update its firmware on our own? The firmware updates use a DOS based utility to update the USB3.0 chipset's firmware.