If a fan is really stiff it is most likely seized or near enough so as to be useless.
You need to trace the circuit, the fans are I am sure controlled by the ecu on these ?, so you need to check it has the earth there, then disconnect the multi plug add earth and live and see what happens, in all likely hood you will need at least 1 new fan.
The tyre wear could be caused by many things, such as broken spring, bad wear on TCA joints, worn bearing to name a few obvious ones to check.
tabetha