On strike days Avanti run services from Manchester to London operating via (but not calling at) East Didsbury and Wilmslow, so that gives an idea of one available route. TfW Rail could also run Manchester-Wilmslow-Crewe (skipping Stockport) if they had resources to do so.
The Drax freight trains, that are classed as essential, run via Chat Moss on strike days. Usually they run via Northwich, presumably due to pathing constraints on Chat Moss. That presumably means Chat Moss is open for some passenger services but not a full service.