It's probably only a minor point but Rafale refuels at about 3 times the abysmally slow rate of the TypHoon, as was noted by the RCAF during the Libyan campaign. Thus when flying CAP, more Typhoons than Rafales would be needed as their off-station time would be significantly greater.
Whereas the F-35A cannot refuel from any Canadian tanker in its current form. And if the Canadians were to specify an unique version with a probe, they would have to pour yet more money into the Lockheed black hole of F-35 development costs.....
More significantly, either Rafale or F/A-18E/F offers twin-engine safety, which over the icy wastes of Northern Canada must surely be more of a consideration than 'stealth'?