As long as you can Boot From USB you should have No Trouble using it to Recover from a Bad flash. Just Flash the modified Bios from the USB in DOS with AWDFlash and it should NOT cause any problems.
No. ISA seems to be the best/safest Method for these Zotac MB's. If you really want to Brick you MB then download the Award SLIC Tool and do it yourself because I won't upload Mods that I think will Brick a MB. And ASUS does NOT use Zotac MB's so these would NOT have an ASUS SLIC.