1. Can I extend the desktop without a dummy plug?
Y
ou will need a dummy plug or 3 resistors to simulate a monitor.
2. Safe temps are the same as nvidia correct? Under 80 is nice, 90 max or so.
ATI Stock fan profiles are less then ideal, concider using riva tuner and setting up a personal profile to keep that beast cooler.
3. Same methods as I use on multiple cards can be applied to a multi gpu card ie folder's gpu-0, gpu-1
Correct
That is a tremendous card for folding, let me know what your getting for ppd when you get it sorted out