Aside from some of the other points mentioned, they would also need to be 4-car to allow for permissive working at Manchester Airport as the curtailed Northern service would likely need to arrive on the B end.
I don't believe Alderley Edge is a proposed call
Looking at the existing timetable, towards Manchester I suspect platform 1 is achievable by extending the existing WMT path, but would only be the minimum 2 minute dwell. On the way back I think platform 1 would be used by Northern until it departs at xx:46. I doubt WMT would want to use the existing Northern path as it sits at Wilmslow for a while and also does not give them a decent turnround at the Airport. So the only other plausible gap is to run later but before the next Avanti arriving at Wilmslow (to Manchester). That only leaves platform 5 available at Crewe which would be interesting. Or you'd have to run even later but I imagine that loses a path further south to Birmingham.