It might fit if they have a mounting spacing like GPU coolers. Certainly seems small enough. I couldn't view your model on the site though. Otherwise you have to create a base yourself.

Yes, on my CPU card revision it is safe to remove the original fan and leave the power wires disconnected. I did it on my 1GHz G4 card. No resistor needed.

Make sure that you insulate the ends (so no blank copper) of the cut wires, otherwise you might create a shortcircuit.