Awesome! Right as I was about to post my response, it crashed again :P
0. I'll try to personally verify this soon. I know the symptom happens with older kernels (not sure of 18.104.22.168 specifically) because I have a friend running a dual-core Opteron that has experienced the same instability problems with 1.0-8762. He does not use release candidate kernels.
2. Can't boot without noapic and can't boot with normal ACPI. The board is an ASUS P5GDC-V Deluxe.
3. No, but I'm pretty sure it is.
My friend hasn't reported his identical problem (well, same symptoms anyway) yet because this forum won't take a free e-mail address. When I speak to him again, I'll fetch a copy of his bug report and post on his behalf.