Even if the AF would have been on the legal minimum fuel for landing in YYZ, they would still have the fuel on board for a diversion.
The KLM rightly advised ATC of their situation, as they apparently wanted to divert without delay, and that has absolutely NOTHING to do with "fumes" in the fuel tanks.
Before you make such a wild statement, do you know how the fuelcalculation is done? Please read the JAR or FAR first and then come back to this forum!
You don't switch "the autoland" on for landing, there is no such switch. In low visiblity ops, you leave the autopilot on untill after landing. This is done in FOG, that means hardly any wind and low visiblity.
Bad weather connected to thunderstorms has nothing to do with autoland, as you will probably be out of limits (1) and the autothrust of the A340 will in my experience do a really bad job as it is not designed for the huge windgusts which I guess you will encounter in such weather on final (2).
P77