I may be wrong, but I don't believe the early cancelations are a result of the mechanics being off the job. I think they are a result of before the mechanics left the job they took the planes out of service and they can not get back into service until a mechanic (ie.the replacements) get in and fix and/or authorize the plane to fly again.

I don't know all the legaleze about aircraft maintenance, but it seems like a large percentage of planes have been "down for maintenance" since the cooling off period begun. So, technically they are a result of the strike, or at least the build up to it. But not a direct result of the mechanics walking off the job. I think it was more of a "Lets see how much damage we can do before we leave" type of thing.