I'd go with May as the preferred month for two reasons:
First, February has Presidents Day right in the middle of the month. For 2020, it will be Monday, February 17th. As a national holiday, a lot of locals and others use the holiday to bookend a quick trip to
Disneyland. With May, the first 3 weeks of the month are fine and you just have to avoid the Memorial Day holiday at the end of the month.
Second is the weather--not in Anaheim, but in other places if you don't get a direct flight. The weather in Anaheim in February is like you described--the low's will be in the high 40°s or low 50°s and the high's will be in the high 60°s to low 70°s. It will be nice and I wouldn't worry about clouds or rain, unless you want to spend a lot of time at the pool.
But if you don't get a direct flight, there may be flight delays trying to connect to John Wayne or one of the L.A. area airports. I'm not sure what part of Canada you'd be coming from, but if you were flying out of Montréal and connecting through Chicago, Dallas, Atlanta, Denver, etc., you should expect flight delays. However, if you're coming down from Vancouver, then I wouldn't worry about the weather so much, as long as any of your connecting flights are West Coast flights.