Could a firestorm create a hurricane-like cyclone?
I don't think so. A large fire could generate a circulation with strong low-level convergence and upper level divergence that would cause subsidence as the air radiatively cooled. If the fire were stationary and huge, the Coriolis effect could make it's upper level outflow turn, but I don't think an intense hurricane-like cyclone could form unless the fire were actually relatively small (like the eyewall of a hurricane), but in that case I'm not sure that the necessary pressure gradient could be maintained (even if the fire could somehow continue to be fueled).